Magic Kiss

Some kisses are so sweet that they feel like magic, but some kisses actually are magic. A Magic Kiss has some supernatural effect that either binds or releases a spell, for weal or woe.

While it's often used as an excuse for Fan Service or ship teasing in modern works, chaste examples of fairy tale magic kisses are Older Than Steam.

Most of the examples of Magic Kiss fit into its subtropes:

True Love's Kiss is the solution to 99.9% of magical curses, and is very common in Fairy Tales.
A Magic Contract Comes with a Kiss: pactio your way into to someone's heart.

Intimate Healing qualifies as a magic kiss if it isn't, well, more intimate; the literal examples of Kiss of Death may also be a magic kiss. Kissing Under the Influence could be the result of magic, but isn't magical itself. Compare Heart Beat-Down and Kiss of the Vampire.

Examples of Magic Kiss include:

Anime and Manga

In Outlanders, Kahm gives Tetsuya the ability to understand her alien language with a kiss. Though later they cast an area-affect version of the spell, probably so Kahm didn't have kiss the entire Nuba tribe.
In Revolutionary Girl Utena, Anthy would kiss Utena's sword (which she had just pulled from Utena's chest) to "abandon her body and protect the sword". Freud Was Right, indeed.
The 'Kiss Of Life' from UFO Princess Valkyrie is both this and A Magic Contract Comes with a Kiss. Specifically, when Valkyrie first uses the Kiss Of Life to save Kazuto by injecting him with half her soul, it's a case of a kiss contract... but subsequently, after she's wound up in Sleep Mode Size, she could 'reconnect' with the missing half of her soul and temporarily regain her magical powers by kissing Kazuto again - which would be another Magic Kiss.

Comic Books

Starfire of the Teen Titans can learn any person's language with a touch, but she chooses to do it with a kiss because it's more fun that way.

Fan Works

Similarly to the Oz example below, the deity going by the name "Wetter Hexe" places a Celestial Mark on Douglas Sangnoir -- and later, on Lisa Vanette -- by kissing their foreheads, during the events of Drunkard's Walk II.

Film

Superman II. The "kiss of Laser-Guided Amnesia" Superman gives to Lois Lane at the end of the movie.
In the Lindsay Lohan film Just My Luck, the main characters can swap their Born Lucky and Born Unlucky status with each other by kissing.

Literature

Glinda gives Dorothy a kiss which marks her as under the protection of the Witch of the North in The Wonderful Wizard of Oz.
The Dementor's Kiss in Harry Potter.

Live-Action TV

Cordelia gets Doyle's vision power when Doyle kisses her in Angel. She later also passes a vision to Angel that way.

Tabletop Games

Succubi and Incubi in Dungeons & Dragons (all the way to the 1st Edition) have an energy drain attack delivered though either a kiss or a hug.
Both Forgotten Realms sourcebooks and novels by Ed Greenwood had spellcasters delivering touch-spells with an extra kink. Magic Missile Reflection spell in The Seven Sisters was called "Shalantha's Kiss" because its inventor was always casting it on her adventuring band like this. Elmara in The Making of a Mage, trying to keep things silent, hits a surprised opponent with a Fleshflame spell - a kiss so hot that when it ended the smoke trailed from that guy's ears, literally. In Elminster In Myth Drannor Symrustar Auglamyr triggered a pre-set spell much the same way.
- Same goes for magic marks - the only described instance of a rare spell "spellsingers' luck" involved a permanent silvery lips mark on the recipient's skin. Seven Sisters did cast in a similar fashion fate link and some beneficial spell. In the latter case Storm blew a silver "kiss" that flew from her mouth to the recipient's cheek and attached there as a tattoo-like mark.

Video Games

Chrono Trigger: Ayla's Kiss ability heals your party members' health while confirming her Bi the Way interest in strong men and women.
Freedom Force: Eve's Kiss is so powerful that make enemies have a temporary Heel Face Turn.

Web Comics

In Homestuck, this is a SBURB game mechanic. If a player dies (and if they have an intact dreamself), they can be revived if another player kisses their corpse within an unspecified time limit (if time runs out, the wounds propagate to the dreamself, killing them too).
Chuckle-A-Duck shows this how it is.
Oglaf has several variations, including magic prank version and "loathsome beast" (SFW pages).

Western Animation

In Teen Titans, Starfire can learn new languages with a kiss, which makes her the Team Face. The comic book version could do it with any touch but usually used the ability with a kiss, but it was distilled to just kissing in the animation.