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 their own skill level better than to tackle description of this kind; there simply might not be a way around the fact that sex is ridiculous for everyone but the people involved. By contrast, 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 careful writer plans for the contrast and makes it meaningful.
- A weird example coming from a series like Berserk. All sorts of graphic sex scenes — consensual or not — and various performances are depicted in the series, the Official Couple not excluded. While Guts and Casca are clearly seen having vaginal intercourse (in four different positions, no less), there is little to no detail of Guts performing cunnilingus on Casca aside from Guts spreading her legs apart and telling her to get ready and Casca looking down and then shuddering and moaning in pleasure. So it's really more of a chaste lust, lewd(ish) sex scene.
- The bonus epilogue chapter of Domestic Girlfriend, "Memories with Rui/Days with Hina", is an example of this. While both Rui and Hina are major love interests for protagonist Natsuo, "Memories with Rui" is depicted as pure carnal desire and is the most sexually explicit of the two stories; meanwhile, "Days with Hina" only features one implied sex scene, happening after establishing a First-Name Basis and declaring their love for one another.
- The Hole has this in spades. 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.
- In Picasso Trigger, both Hope Marie Carlton and Bruce Penhall are both naked in a jacuzzi and when they kiss, the camera cuts away.
- In Plan B, Bruno and Pablo get many UST-laden scenes of them undressing and sleeping in the same bed with just their underwear on, but their attempt at having sex together is incredibly awkward and only goes as far as them removing their shirts before they break down into nervous laughter and call it off. When they're finally fully ready to have sex at the end of the film, we only see them pulling each other into the bedroom before the credits start rolling.
- Marco Berger's later films after Plan B fit this trope even better. Hawaii and Taekwondo are both teeming with handsome men who spend at least 90% of their screen time without a shirt on, get multiple Male Frontal Nudity scenes and Unresolved Sexual Tension with each other so thick it could be cut with a knife... but the most action these men get with each other are a kiss at the very end of their respective films.
- 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.
- and i'll do anything you say (if you say it with your hands) by nebulastucky on Archive of Our Own was originally rated Explicit due to a scene at the end of the first chapter, but was revised down to a Mature rating after the author realized that "it felt more fitting with the tone and content level of the rest of the fic". Something happens between two characters in a bathroom stall; it is built up to, then tastefully elided by the author simply cutting to the aftermath.
- 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.)
- In an Older Than Feudalism example, The Song of Songs describes the anticipation and meetings between two lovers in rather racy detail, but the part about the actual intimacy is absent.
- In A Brother's Price, all the sex scenes are like this. While it is only touching with clothes in between, we get full details, but once the clothes come off, it's only hinted at what they actually do. The scenes where we actually are told what goes where, with no cut, are the ones that aren't meant to be erotic.
- The Hunger Games: Katniss and Peeta share a make-out session that describes the kissing and the way it makes her feel in great detail. When they eventually have sex it's given so little detail that there's room to argue they didn't even have sex at all.
- The Last Herald-Mage Trilogy stars Herald-Mage Vanyel, one of the first gay male protagonists in fantasy. While his love life — both good and bad — does factor into the plot, there are no explicit sex scenes, just the lead up, perhaps a bit of text from a third party's perspective to tell you what's going on, and straight to the post-coital bliss or trauma.
- 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.
- 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.
- Orson Scott Card's "The Originist": When Deet and Leyel have sex on the living room floor, it's only two sentences. However, their post-coital nuzzling is given multiple paragraphs of description.
- In Sunshine, two characters at one point have very pleasant sex outside in the sunshine...and that's all we're told about that. When two characters stop at foreplay, the reader is given all the details up to and including how unhappy the viewpoint character is at stopping halfway through.
- The Twilight Saga goes into detail about Edward and Bella making out, but the various sex scenes in Breaking Dawn were faded to black.
- Leisure Suit Larry 1: In the Land of the Lounge Lizards. After a game's worth of dirty jokes and innuendo in the quest to get Larry laid, impending success causes the game to switch to a black screen for fireworks and a developer's congratulation.