No-Effort Nookie

Generally, entering a sexual relationship with someone involves a level of trust, willing consent, and in non consensual situations (such as rape), domination by force, all of which require some degree of effort on the party wanting the sexual congress to begin.

And then there is this trope.

This is when the sexual encounter happens with no effort on the part of the person wanting the sex, or so little effort it doesn't really count as making one.

In general

 * This trope is why porn with no plot whatsoever exists in the first place.
 * This can also happen when one or more parties are drunk or high, sex usually being the result of that person(s) wanting the sex being aroused and the usual reservations on needing to know and trust the other party go out the window due to diminished judgment.
 * Prostitution requires money (or a substitute) on the part of the party wanting sex, but otherwise no other actual effort is needed, since sex is the service being sold in exchange for another good or service.

Anime and Manga

 * In Neon Genesis Evangelion, Gendo Ikari manages to have Naoko and Ritsuko Akagi sleep with him, having to exert no effort at all besides letting them know he's interested, and this guarantees him sexual relationships with both women, who wanted him since day one. He wanted the sex for his own reasons, but he didn't have to do much on his end to get it to happen.

Video Games
"Hey Kinize, wanna fuck?"
 * In Saints Row IV, getting Kinzie to sleep with the Boss is as easy as walking up to her and asking: