Deus Sex Machina

Maybe you're a master of ancient tantric magic. Maybe you're part incubus or succubus. Maybe you've just got a big ol' can of Applied Phlebotinum... in your pants. Who knows? For whatever reason, your plot-related powers or items refuse to turn on until you're turned on... the story can go no further until you go all the way... you can't get on with the plot until you've got it on with... things don't work out until you make out... it won't do if you don't do it... If all you have is a hammer, every problem requires you to nail... okay, I'm done.

A Deus Sex Machina is any speculative fiction contrivance for inserting sex where it would otherwise be implausible. When used properly, this trope can be used to explore sex-as-metaphor. When used poorly, it's just an excuse to dress up pornography as plot. Most examples probably fall somewhere in the middle. Incidentally, semen has traditionally been associated with vitality, Life Energy, holiness, etc in various cultures, and the sex act itself with fertility (agricultural, that is) rites and seasonal change, so there's a bit of mythological justification for this trope.

Naturally, plenty of phlebotinum works the opposite way.

Overlaps in places with Intimate Healing and The Power of Love. If the Deus Sex Machina had not been foreshadowed before in any way, it's also a case of Coitus Ensues. See also Mate or Die, Aliens Made Them Do It, and Level Up At Intimacy 5.

If you're looking for the trope about actual deities having romance or sex, that's Divine Date.

Anime and Manga
""In order to stop a truly powerful enemy, you had to have sex with two women at once, and that it actually made one of them powerful enough to win against a foe you had no hope of defeating before?""
 * Seikon no Qwaser is a truly strange show that goes a bit beyond propping plot up with sex. People with magic powers to control elements—not the 4 elements but from the periodic table: Iron and Copper are principal characters and Gold is some kind of villain—but in order to use their powers they need "Soma" which they get from sucking on enormous tits. Evidently, they must be large tits. In any version readily available, every plot-related scene is heavily censored, to the point that it is impossible to know what is happening—at least story-wise. It's hard to hide what the characters are doing.
 * At the time of this writing, there are uncensored versions available (hint: do a google search for "seikon no qwaser uncensored"). They're a lot easier to follow. And bouncier.
 * Generally speaking, this is actually a huge problem in the Japanese "nerdcore" industry, especially with semi-professional video games and animated projects. Full-blown porn is still considered a shameful thing to produce; however, including blatant sexuality in a work even when it doesn't make a lot of sense or is a bit disjointed from the narrative guarantees sales from a certain section of the population, and a lot of companies have built their initial fortunes this way, despite the damage to their reputations and the fact that the sexual content is often shoe-horned into stories that are more than narratively sound enough to stand on their own without this kind of "propping up". Nasuverse and Key games (such as Kanon and AIR) are the most notorious examples of this practice, although it's worth pointing out that those involved with said franchises are now bleaching furiously since the initial appeal of sexuality paid off.
 * Considering the fact that TYPE-MOON's popularity exploded after Fate stay night, but that they still continue to add nudity, shows that it wasn't simply for sales appeal.
 * Key games do not even bother trying to pretend that the sex is in any way important to the plot. Pretty much 'we know you thought she was cute, here's a picture of her naked, back to the sad story.' Which is why they made an under 18 version of AIR (for those who just want the story) and CLANNAD, which doesn't have any sex involved.
 * Kano in AIR is told by that she will gain magical powers once she "becomes an adult". In the original H-game, you can guess which way she takes this. (Pun very much intended.)
 * The entire premise of Magic Woman M. The main character can only use her full magic when she gets in the throes of... well you get the idea. Basically making an excuse to have some of the strangest rape scenes ever (lizard critters that implant eggs into people to make more lizardfolk, for instance)
 * In the movie Ninja Scroll, one of the ninjas was able to control women. Initiating this mind control involved the victim tied spread-eagle and naked from the waist down while the ninja licks his fingers to lubricate them. Further details not needed.
 * The woman in question was incredibly poisonous; having sex with her led an otherwise unbeatable rock-man to.
 * A prime example of this is Daiakuji, where the protagonist comments upon his release from prison about how he has become weak with absence of sex. Throughout the series the protagonist becomes more powerful as he subjugates women.
 * In the anime I Dream of Mimi (aka Buttobi CPU), Akira's humanoid PC, Pixie, can perform all manner of miraculous feats from defending him from other hostile humanoid PCs to magically repairing any resulting damage. However, she can only do this if Akira provides her with the sperm she needs upgrade her memory to sufficient levels.
 * La Blue Girl involves ninjas who use sex (and things related to it) as weaponry. Case in point, pubic hair needle barrage. Delivered at point-blank range to the eyes.
 * Considering the vaginas that squirt acid or bite off penises and orgasm-triggered disintegration, you have to wonder how any of this made the sex less terrible.
 * Cruelly subverted in Basilisk, where one of the Koga ninjas is Kagerou, a beautiful and sexy Broken Bird who will never be able to have sex with a man she truly loves since her breath becomes poisonous when she's aroused.
 * It's implied in the anime and stated outright in the visual novel that one way for a Master to recharge their Servant's mana in Fate stay night is to have sex with them. There are other ways, but sex is the only one Shirou isn't morally opposed to (like say, draining the lifeforce of innocent people for mana).
 * As one fanfic put it:

""My ejaculatory control muscle is at its limits!""
 * In a similar vein, in the Tsukihime Visual Novel the Synchronizers' ability work through fluid exchange, as well as in an earlier route. Meanwhile, the pseudo-sequel Kagetsu Tohya is a subversion, as there's a perfectly viable alternate solution you can take, Len just doesn't like it as much. Hey, he is Shiki Tohno.
 * In Urotsukidouji 2 Hitler's ex partner in crime uses Amano's sister as a 'sacrifice' to open the gates to the Makai world, allowing demons to come to Earth. To do this, he gives the powers of the Chojin's enemy, Kyo-o, to the lead character's best friend and he has rough and rather graphic sex with Amano's sister, Megumi before fighting Chojin. Lovely.
 * In the h-anime Jiburiru - The Devil Angel, the titular Magical Girl's powers are not only charged by sex, but different kinds of sex unlocked different attacks (For instance, anal sex unlocked Jiburiru's Angel Cutter and masturbating in front of someone unlocked her Angel Dynamite attack).
 * Similarly, in Beat Angel Escalayer and its sequel ''Beat Blades Haruka" - the device that powers the titular Magical Girls' abilities can only be charged by strong sexual arousal.
 * The giant mechas in the anime Raimuiro Senkitan are powered by someone having sex with their pilots.
 * Giant mecha in Inyoku Tokkyuu Zetsurinou work similarly. It's confusing as to how they pilot the mecha at the same time as producing energy for it. Oh, and its main attack is a penis made of Pure Energy.
 * In Amaenaideyo!!, Ikkou is a male novice at a Buddhist temple populated by a harem of miko Buddhist nuns. His powerful spiritual ability for combating ghosts and such is unleashed via lust, so the plot resolution is invariably one of the girls disrobing, or being disrobed, in order to release his power.
 * Crimson Spell offers up a twofer: the sorcerer Havi keeps Prince Valdrigue's Super-Powered Evil Side under control with sex, which apparently also has the effect of helping fuel Havi's own magical powers. Go figure.
 * Dragon Pink features an elven mage, Pierce, recharging her Mana by having sex. In the midst of a fierce battle, no less!
 * The Gantz anime toys with this: while Kurono is still unused to using the Gantz suit, he theorizes that it only functions when he is turned on. This theory is only referenced in one scene and the suit seems to function consistently after that, so either Kurono was wrong and the suit also responds to other kinds of "excitement," or he's turned on a LOT. (Knowing Kurono, the latter is at least as likely as the former.)
 * Inverted in the oh-so-wonderfully named manga My Balls. The series begins with the Queen of Terror being sealed into Satou Kohta's right testicle, meaning the world will end should he ever, well, um, you know. Cue the sexy legions of Hell to use every technique in their arsenal to get in his pants, hilarity ensues.


 * In Genesis of Aquarion and its sequel Aquarion Evol combining mechas causes all of the pilots to experience something Better Than Sex. Each time they combine, the audience gets a load of screaming, rainbow-coloured naked bodies. The entire series has multiple metaphors to sex and maturity, but those are justified due to many of the characters being teenagers.
 * Moonlight Lady deals with this a whole lot. Apparently, the training that Suzuna has to go through in order to carry out the Expecting Moon Ceremony involves loads and loads of Pornomancy, not to mention the fact that simply because Expecting Moon Ceremony is about to begin makes everyone start rolling around in the hay. Oh, and wouldn't you know, the Expecting Moon Ceremony itself is ! Suzuna's mother, Yuriko, also seems to have powers that make people lose their inhibitions, not to mention.
 * Played ridiculously straight in Yuria 100 Shiki. Yuria is a Sex Bot trying her best to not be one. However, despite her best efforts, she inevitably winds up rationalizing some reason to have sex with Shunsuke. Hilarity Ensues.
 * Urd from Ah! My Goddess tries to invoke this trope in her introductory chapter of the manga. She tells Keiichi that he has to have sex with her in order to repair/recharge the system force that keeps him and Belldandy together, and that if he doesn't have sex with her, Belldandy will have to return to heaven. It turns out to be a trick though and Belldandy comes in and reveals that it was just a trick before anything happens.
 * Kinji's Hysteria Mode from Hidan no Aria only gets activated when he becomes sexually aroused.
 * This happens in the final episode of Panty & Stocking with Garterbelt when
 * in the 11eyes anime. In episode 11, Misuzu has sex with Kakeru to power him up (or something along those lines). ..

Comic Books

 * Phil Foglio's XXXenophile sometimes uses this, but usually with a comedic twist. For example, the one where the nymph mentions casually in passing that people's orgasms keep the earth from exploding, or the one where a time traveller from the future has to find out whether it's worth bringing back women through cloning, but it turns out.
 * The old Penthouse ComicX series loved this trope:
 * Hericane's powers came from a combination of explosives... and a mouthful of Captain Adventure's (the current one's father) baby-batter.
 * Dr. Dare was a Distaff Counterpart Captain America (comics)-Doc Savage hybrid who gained temporary super strength after an orgasm. (Unfortunately for her, masturbation didn't seem to work)
 * In Scion (NOT the Cross Gen one), a dormant Scion's powers could only be activated through sexual contact with a Scion with active powers.
 * In Alan Moore's Promethea, Jack Faust agrees to teach Sophie Bangs about magic in return for sex with her alter-ego, Promethea.
 * Hellblazer - In the Fear Machine arc, Constantine and his two ex-girlfriends (a hippie and an earth goddess priestess) save the day with a threesome (and "female" magic). The two ladies had spent the previous few months on an island (a character calls it "one of those woman magic places") where the magic was powered by love and orgies.
 * The John Byrne comic Next Men has sex with the Next Men as a catalyst which bestows super-power mutations on normal humans.
 * In Top Ten: Beyond the Farthest Precinct, the Hell Ditch Pilgrim is revealed to have gotten his powers in the previous Top Ten series by catching S.T.O.R.M.S., a mutating disease, from a prostitute.
 * Valiant Comics' Shadowman had to have sex with young-looking Voudun priestess Mama Nettie on a regular basis to keep her young and powerful, so she could help him control his mytical Dark Side.
 * Pandora Breedlswight from Ironwood is possessed by a demon that can be summoned at will (taking her place), but can't be dismissed by anything else than an orgasm. This is part of a family curse, running on male members, until Pandora happens to be the last of her line. Her male ancestors seemed not to care of the curse, anyway.
 * In the Buffy the Vampire Slayer comics, Willow uses the power of orgasms to power the spell used to contact her patron goddess, Saga Vasuki.
 * In Hack Slash the female slasher Acid Angel has corrosive vaginal juices as her main weapon. Ew.
 * In Jean Van Hamme and Grzegorz Rosinski's comic Le Grand Pouvoir du Chninkel (The Great Power of the Chninkel), Volga the Soothsayer must have an orgasm in order to deliver propheties.
 * Provides Fan Disservice in Incorruptible #16, where the city's water supply is magically transformed into some noxious substance by the unattractive and obese sex magicians Nebuchadnezzar and Loretta Grass, whose spells only last as long as they're "chanting".

Fan Works

 * In the extensive Star Trek Alternate Universe Fic Firing Solution, Pon Farr and the Vulcan mating cycle and cultural history are examined in far more depth, and at least half the mechanics of The Federation and the power shifts in the galaxy prove to be directly attributable to Vulcan Nookie.
 * In a True Blood/X-Men crossover Survival of the Fallen, it turns out that is a succubus. In this case Succubi aren't outright demonic, and appear to go either way morally speaking. They seem more like talented sex oriented energy vampires, without actually needing to take energy. Considering the character this happens to, this is most ironic, and a major plot point.
 * The Neon Genesis Evangelion doujin RE-TAKE, takes this to... a much lower level than would be expected, considering the author's previous work! This is done properly in chapter one. All 5 chapters thereafter just play dress-up-the-sex-and-hope-the-audience-doesn't-notice.
 * In Chapter 34 of Light and Dark - The Adventures of Dark Yagami, the Creepy Chick turns out to be able to time travel via "lots of sexing".
 * This is essentially the premise of Pokegirls—the eponymous semihumans are normally bestial and dangerous, but sex (or rape) temporarily restores their minds. This leads in weird directions...

Film
"Zuul/Dana: I want you inside me. Venkmann: It sounds like you've got at least two or three people in there already... might get a little crowded."
 * In the original Ghostbusters, it's strongly implied that Dana Barret, while possessed by Zuul the Gatekeeper, had sex with Louis Tully, who was possessed by Vinz Clortho the Keymaster (key, gate, get it?), in order to free Big Bad Gozer. In fact, a deleted scene from the movie has Venkman explicitly asking Dana if she and Louis "did it".
 * Almost certainly related to an earlier, often deleted exchange.


 * In the 1987 Rom Com My Demon Lover, the hero is under a Gypsy curse that makes him turn into a demonic monster whenever he gets turned on. When his love interest is captured by the real (and likewise cursed) monster of the story, her best friend seduces him to enable him to make the transformation and fight the bastard. (This makes the love interest jealous, despite the obvious necessity.)
 * Averted in one of the Ghoulies films. A would-be Satanic wizard paints a ritual pentagram under his bed, then attempts to have sex with his female companion there. Realizing that he's chanting under his breath, she catches on that it's one of his sick magical experiments, and kicks him out of bed.
 * In the Israeli film The Revenge of Isaac Finkelstein - there's a ghost of an ancient monk who's invisible to everyone except the protagonist, unless he has a hard-on, which makes him visible (or semi-transparent, depending on the hardness of his 'on').
 * In the movie Zerophilia, people with the "Z chromosome" change gender when they have sex with another person with the Z chromosome, or (when their powers first manifest) simply when they reach orgasm. (No, it's not quite as pornographic as it sounds.)
 * In Cat People the remake, the werepanthers' transformation is triggered by sex.

Literature

 * In Stephen King's IT (but not in The Film of the Book for obvious reasons), Beverly Marsh . Apparently it's supposed to be a metaphor for moving from childhood to adulthood.
 * Another level of irony (and possibly a Family-Unfriendly Aesop) also exists here, when you contrast this with another scene in the book. Beverly's father is portrayed as an abusive, overprotective, borderline psychopath. When he learns that Beverly has been playing with boys, he insists—violently—on physically checking to see if she's still a virgin.  At this point, she still is, and the scene plays out like an attempted rape.
 * The real irony of the matter is that Beverly is inspired to because of what her father did. He put the idea in her head.
 * Stephen King might do this a lot. In his Dark Tower series,  In the series, oracles are demons that feed on sexual energy (i.e., incubi/succubi). Go on, guess the best way to distract one.
 * The Wild Cards series has several examples:
 * Fortunato has "magickal" powers that must be fueled by tantric sex. Fortunately for him, he's a pimp with easy access to geisha-style prostitutes.
 * The character of "Blowjob" must be sexually excited in order to breathe life into inanimate objects.
 * Roulette can kill by unleashing poisonous vaginal secretions. (Does somebody have issues?)
 * "Prime" was able to give the "Jumpers" their power to switch minds with other people by having sex with them.
 * after being infected by the Sleeper's new strain of Wild Card virus.
 * Genetrix lay eggs which hatch into short-lived children with ace powers fitting her needs when engaging in sex.
 * The eponymous protagonist of the Anita Blake series has had her supernatural powers become more closely tied to sex with each passing book, resulting in a situation where the solution to any problem is for her to have sex with somebody or something. That makes this also an example of When All You Have Is a Hammer... or possibly, in this case, a screwdriver.
 * And in the same author's Merry Gentry series, it's eventually explicitly stated that the power of Faerie comes from the natural order and thus can only be awakened through fertility rites. This does allow the choice of sex or death (killing in battle or sacrificing loved ones), and Meredith isn't always viewed favorably for favoring the "soft" option (except by the beneficiaries of it). Since the protagonist here has been chosen to revitalize the entire magical world... this series basically starts sexually at the point Anita Blake was at that time, with a main character who never had any of Anita's former inhibitions.
 * In Larry Niven's Ringworld series, depending on the particular human subspecies involved, when two inhabitants from different subspecies meet, the standard greeting may be ritualized sex ("Rishathra" is the word for this among the species our protagonist meets in The Ringworld Engineers), though for some cultures it is taboo. (People still talk about Niven showing up at a sci-fi convention in the late 1970s wearing a button that said "I have sex outside my species.")
 * In the later Dune novels, an offshoot of the Bene Gesserit arise who use sex as a form of hypnosis—it's just that good, apparently. Numerous galaxy-spanning, wheels within wheels plots are derailed when it is discovered that there is a man with the same power. A-whoops!
 * And this man trains other men to use that power. Leading to a guerilla war fought mostly using SEX. Really awesome sex. Where do I sign up?
 * In the Illuminatus trilogy, the goddess Eris has sex with multiple men to return to God mode. The insanely high amounts of sex in that book build up a pretty good reader tolerance to implausible sex acts, but that one takes the cake.
 * In the The Book of All Hours duology by Hal Duncan, especially in the second book, "Ink", tantric sex apparently makes it easier to travel between the various alternate realities. Several kinds of technology also seem to be fuelled by sex, using so-called "orgone energy" as a power source.
 * Jennifer Stevenson's Trash Sex Magic is entirely about this trope, as its title might well imply.
 * In Michael Swanwick's The Iron Dragon's Daughter, protagonist Jane learns to use sex magic to boost her own spellcasting ability.
 * Inverted in S.M. Stirling's alternate-history novel The Peshawar Lancers: The heroine has been (incestuously) bred for clairvoyance; this power (1) only works for virgins and (2) ultimately drives the holder to madness and death. You can guess what the hero does to save her.
 * In American Gods, a perversion of the Queen of Sheba
 * Also, there is importance in
 * Not to mention the
 * In Dan Simmon's Olympos, one of the main characters finds a slumbering princess who's been kept in stasis for centuries. The only way to wake her? Climb in the stasis chamber and give her some lovin'.
 * Ramona Random, a Black Chamber agent in Charles Stross's The Jennifer Morgue has a succubus bound to her. If she doesn't have sex, it eats her mind. If she does have sex, it kills the partner instead. She's employed as an assassin, naturally.
 * This is how the story of Sleeping Beauty originally went, though now that version is usually titled Sun, Moon, and Talia to differentiate it. She stays asleep until she has twins and one of them suckles the poisoned needle from her finger.
 * One version says that what wakes her up is her first baby's cry.
 * This happens with Leah, Henry, and Tony in Smoke and Shadows Leah is tied via Demongate to a sex demon named Ryne Cyratane, but the demon doesn't comprehend homosexuality. Tony the gay wizard can tell that Ryne Cyratane wants to communicate with him, but literally can't see him without the sexual connection. Ergo, Tony's Bi the Way ex Henry is enlisted for a save-the-world threesome that will enable Tony to talk to the demon.
 * Kushiels Dart and its sequels contain any number of Deus Ex Machina scenes where the main character resolves whatever problems exist in the kingdom through having sex with someone. This is because she is magically gifted with really enjoying every kind of kinky sex...
 * Perfume: The Story of a Murderer. It's funny what you can accept when the movie logic is introduced early and kept consistent, really...
 * Same for the film of the book.
 * The Secrets of Jin Shei - although Lihui is a powerful mage without resorting to this, it's implied that he can only keep his strength and immortality by stealing other people's energy.
 * In Battle Circle by Piers Anthony, the heroine is trapped in a Minotaur's maze. The hero goes in to rescue her. He finds her but they are unable to escape and the Minotaur is closing in on them. The hero remembers that the Minotaur is only interested in virgins and he can save the heroine's life by another means.
 * Dragonlance: Heroes: Vol. 1. Huma, Knight of the Sword. One of the final gambits of Takhisis, Queen of Darkness is that she could show him... things. He refuses.
 * In A Song of Ice and Fire  is able to spawn shadow demons that can be used as assassins. She needs sex in order to create them, but it apparently weakens the man she uses; she herself states that   declining health is due to her using him in that way, and so tries to convince   to help. It is possible that her somewhat Foe Yay-ish interactions with   might be a prelude to trying to use him in this way.
 * In Alex Prentiss' novel Night Tides, the main character communes with lake spirits, but in return, she must help everyone who needs it.
 * In Peter S. Beagle's The Folk of the Air, there is a fairly random sex scene between an ancient evil spirit in a boy's body and a young (very young) woman for the purpose of "tantric sorcery."

Live-Action TV

 * In Smallville, Clark's discovery of his Heat Vision was linked to him being aroused. I wonder what that reminds you of... Hence the Fan Nickname "Eyejaculation".
 * In The Others, two of the characters have fallen in love, but the interaction of their respective psi-powers causes powerful energy discharges whenever they touch. In the finale, as part of a series of strange happenings that works to break the group apart, they find that they can now safely touch one another. This tragically turns out to be an illusion created by an otherworldly evil force, which lifts while they're having sex. Cue the entire building exploding.
 * The eponymous planet-killing spaceship of Lexx would only respond to whoever held its symbiotic energy key in their brain. The host would involuntarily release the key into whoever else was nearby if brought to the very edge of death... or the very extreme of sexual ecstasy. Interestingly, this was not equivalent to orgasm; actual sex usually did nothing to trigger the key, whereas just the anticipation of sex with a character's One True Love thrice did.
 * Star Trek has Pon Farr - every seven or eight years Vulcans get a hormone craze that is generally only to be satiated by sex. Either they do or die, literally. Fortunately, . Or.

Tabletop Games

 * Mage: The Ascension gave us the Cult of Ecstasy. Sure, they didn't just revolve around using sex as magical foci (they also used drugs, music, meditation, etc.), but that was easily the aspect with the most humor potential.
 * Mage: The Awakening carries it on with a Legacy called the Whipping Boys. They don't use sex, exactly, but BDSM, using deeply intensive "sessions" to find revelation in a place beyond pain and pleasure.
 * Both played straight and inverted in Unknown Armies with the tastefully named magick school of Pornomancy.
 * In Warhammer Fantasy Battle and Warhammer 40,000, the Chaos God Slaanesh and its followers have this reputation, however any excessive and obsessive mindset can cause empowerment in his/her name, not just sex. The Emperor's Children Legion were seduced by Slaanesh due to their single-minded obsession with purity and the excesses they would commit to achieve and maintain it, Noise Marines are focused on extremes of psychically-charged music, and The Masque (most powerful of all Daemonettes) gets its power from basically being the best dancer in the universe, able to entrance even the Chaos Gods.
 * In Bliss Stage, the power of a Pilot's Dream World Humongous Mecha is based on the intimacy level of their relationships. To get the maximum of Intimacy 5 with anyone you're not related to, you have to have sex with them. It's quite disturbing considering the Pilots are teenagers, and the Anchors that produce their mecha and the various supporting characters are either teenagers, or full-out children.
 * This is mechanically discouraged, as well: losing an Intimacy 5 relationship to trust issues can destroy an entire RESISTANCE...
 * One of the many strange and juvenile things that comes with the territory when people publish sex-based supplements for Dungeons & Dragons (officially, the legendarily bad Book of Erotic Fantasy, as well as Encyclopedia Arcana: Nymphology and Quintessential Temptress, with the latter two basically a collection of juvenile snickering). Tantric magic is just the tip of it.
 * And Sisters of Rapture, which kicks it up a notch with full-frontal nudity on nearly every page—some of it showing tavern scenes and the like to drive the point home that these characters never wear clothing at all.

Theatre

 * In Richard Strauss's early opera Feuersnot, Kunrad punishes Diemut's rejection by magically banishing fire from the town until she gives herself to him.

Video Games

 * Completely inverted in Planescape: Torment, where the token demoness is a reformed succubus, runs an Intellectual Brothel and refuses to feast on horny men for her power. She is the healer of the party, but not quite the Intimate Healer; her kisses are an attack. There is a tentative flirtation between her and The Nameless One that suggests the approach of a kiss, but she decides not to risk it, even if he's apparently immortal.
 * A memory that the Nameless One can trigger reveals that he can have sex with a succubus, die, and come back. In fact, he did so, and then gave the memory to the Sensates so that other people can experience it without, you know, the unfortunate end.
 * Actually, he didn't record that memory. Remember, prior to his awakening in the Mortuary at the beginning of the game, he lost his memories every time he died, meaning that he therefore could not possibly have recorded the memory of being killed. Someone else would have had to record that memory then get raised from the dead. The Nameless One might have had a very easy time coming back from the dead, but he was hardly the only person in the world able to do so.
 * In Grand Theft Auto games, players gain health from prostitutes. This method can be used to greater-than-max health.
 * The fourth one added strippers, who unfortunately stay in bra and panties. They heal the same amount prostitutes do, but they cost more.
 * The fangame Quest for Glory 4.5 also allows the hero to be "healed" in a brothel. Needless to say the company owning the original game wasn't too happy.
 * A possible choice at the end of Dragon Age: Origins is for
 * Brütal Legend: Apparently, years of orgy and violence can cause a . It's the Tainted Coils we are talking about, however, it's almost expected.
 * Apparently sex is required to gain the right to in Eien no Aselia. Fridge Logic sets in when you realize that  apparently did not have to. Maybe  made the whole thing up?
 * In Embric of Wulfhammer's Castle, Huraine (goddess of love, lush scenery, strawberries and chocolate) requires this of her worshipers in their rituals, which is good news for Dorcas. One of the Multiple Endings even has the Duchess becoming the centrepiece of one of these rituals.

Web Comics

 * Super Stupor has one comic where a hero reveals his superpower to make anyone tell the truth... as long as his penis is inside them. He's asked how he discovered this power, whereupon a third character claims it's "the best divorce story ever!"
 * Kit N Kay Boodle, all the time. Nearly every plot line seems to be solved by the title characters having sex yiffing.
 * Ménage à 3 features "Everything That Moves" Zii, whose ability to have sex with anyone she wants (except Didi) reaches the level of a superpower, and warps reality around her to make it conform to the rules of a porn movie (with her in the role of the pizza delivery guy). She used this power to get her revenge over a Troll by banging his mom, granting her an instant Flawless Victory.
 * In another story, Zii and Didi are playing with Gary's Transformers collectibles and break a rare one. Not being able to fix or repair it, Zii comes up with a plan - she and Didi will have a threesome with Gary (who's a virgin) and he'll be so overwhelmed by the sex he won't care about the broken collectible.
 * Sonichu, of all comics. has this in issue #8 with Silvana, whose "nectar" is a poisonous and paralytic sleeping agent she secretes during sex. After transforming herself to look like Bubbles, she makes out with Blake, knocks him out, and advances what little plot there is in the comic in the first place.

Web Original

 * Now, the vast majority of Ilivais Xs Humongous Mecha are fairly normal and realistic. But the eponymous one only registers with one who possesses "Love" Drive Core (or has a similar demeanor), but the way it works makes it more similar to lust. This kicks off numerous broad themes involving the border between love and lust and whatnot, but the most clear example of an out-and-out Deus Sex Machina is the Love Drive Core attack, which can basically only be used via orgasm.
 * Go to asstr.org's author's page and look up Stephen Gray (NSFW or kids). Marvel at both the sex as mind control and demons/potions/Aliens Made Them Do It. Notice how vanilla most of the sex is. Wonder if this is a case of the Machina being extraneous to the sex...
 * This shows up a lot in the Sci-Fi and Fantasy section of Literotica, though details vary.
 * The erotica writer Salamando, aka Salamando Flames enjoys mixing elements of fantasy adventure and superhero fiction into his erotica. Often, sex will in some way be used as a mechanism for mind control, domination, acquiring magical energy, exacting revenge, fueling super powers, or even healing. In the Sex Mage World stories, the entire basis of magical powers (which only women have access to) requires sex and arousal to both activate and continue functioning.

Real Life

 * A study suggests sex may boost long-term memory and counter Performance Anxiety in male rats. Nobody knows if it works for humans of either sex, but news editors haven't let that get in the way of a good headline.
 * It has this effect in the only strain of rats that was tested, but it has the exact opposite effect in the only strain of mice tested. So depending on if humans are more like one strain of rats or one strain of mice, sex improves memory and relieves anxiety, or it makes you more anxious and unable to remember. Take your pick. Furthermore, they can only test this in male rats and mice since females tend to get pregnant and pregnancy has a huge effect on the brain region in question. This is why you should not trust a good headline.