Lewd Lust, Chaste Sex

Sometimes, the most explicit acts get the least explicit scenes. It can seem very strange when a French kiss, a make-out session, or other act of non-coitus is depicted far more sexily than actual sex.

The effect is natural enough. There are any number of reasons not to depict a sex scene, and far fewer to shy away from a merely erotic one. Sex may not fit the rating; it may not fit the tone; it may be intended as an act of loving union, and the slimy bits would distract; the author may know better than to tackle description of this kind; there might not be a way around the fact that sex is ridiculous for everyone but the people involved. Meanwhile, tamer acts offend fewer delicate sensibilities, are less likely to overwhelm the plot, and can wind down naturally at levels where cutting away from a sex act would be both awkwardly explicit and frustratingly vague.

The clueful writer plans for the contrast and makes it meaningful. The difference between lust and love is an easy overtone, as is the conspicuous absence of whatever caused a previous failure.

Film

 * In Three Colors: White, a failed attempt at sex is shown in all its glory to establish the desperation of the participants and of their relationship. Success much later on fades to white.
 * The Hole has this in spades (as well as a topless Keira Knightley). Thora Birch and her romantic interest have a standing make-out-and-grope session, while the camera keeps them dead centre. Later, when the love interest takes her virginity, it's offscreen, and all we hear are her not-too-sexy grunting noises.

Fanfic

 * In Seven Things That Didn't Happen On Valentine's Day At Hogwarts, Or Maybe They Did, frenzied 15-year-olds grabbing at everything they can reach are described in detail, but 17-year-olds acting out of love are cause to cut to the following morning. (Also, everyone's gay. But that's another matter.)

Literature

 * A hot'n'heavy scene in Cory Doctorow's Little Brother has a lot of sucking and moaning and lowering and brushing, and that's about when the tear gas comes down. When the couple has actual sex, the description cuts away.
 * Twilight and its sequels go into detail about Edward and Bella making out, but the various sex scenes in Breaking Dawn were faded to black.
 * The Finnish novel Häräntappoase.
 * Shows up from time to time in the Nightrunner series. The kisses are described in great detail, from the physical to the emotional ramifications. But by the time the two leads actually become a real couple, the descriptions largely gloss over any specifics.

Web Original

 * This was standard procedure for love scenes in the Global Guardians PBEM Universe. Pretty much everything leading up to "the act" was on screen and fully described. But once it became a matter of penetrative sex, the focus of the story shifted to the curtains fluttering in the breeze, and things faded to black and restarted the next morning, and so on.