Sex Dressed

We can tell that characters have been engaging in sexual activity from the way they are dressed. Caught in a car, answering the door, at the office, burst in on, etc. Half-undone clothes in disarray is all the explanation we (or the characters) need in order to know what's going on.

This is where the phrase "Caught with Your Pants Down" comes from. See also Sexy Shirt Switch.

Not to be confused with Ready for Lovemaking

Films -- Live-Action

 * In The Dark Knight, when Bruce goes into his penthouse bedroom to the hidden wall panel. In the background you see a man hurriedly stand up and buckle his pants, while the woman he was with adjusts her bra and expresses relief that there is a panic room.
 * In Porky's, the assistant coach comes back with his shirt messed up after the howler's heard earning her namesake. Everyone knew who the woman was but aside from the head coach no one knew who the dude was 'til they saw him w/a mussed shirt.
 * Lampshade Hanging and averting of this trope occurs in Waterdance. The heroine's family finds out about her first and only liaison; a friend refers to it as being "caught with hay in your hair and your skirts around your waist" and she replies that they did it in a bed and took their clothes off properly, thank you very much.
 * In one sequence in Futtocks End, a fuse blows just as everyone is going to bed, plunging the house into darkness. When the lights come back on, everyone is on the landing in their sleepwear; the housemaid and the Boots are wearing each other's pajama trousers.

Literature

 * In the Doctor Who Eighth Doctor Adventures novel Vanishing Point, Fitz gets in trouble due to being seen like this. See, he just had sex with a twenty-year-old ingenue, called Vettul, who has never met a remotely able-bodied human man other than him -- when she first met him, she called him "very beautiful" although he's really just average-looking, because she has no real point of reference. Looking at it that way, there's little space for the fact he's also ten years her senior to make it worse. So her mother-figure goes over all Overprotective Mama Bear when they come back from the barn (yes, they had a literal roll in the hay) and she notices that Fitz hasn't got his trousers properly done up, so they keep falling down, and Vettul looks a little rumpled as well. He tries to talk her down by telling her that she's been sheltering Vettul far too much, which is true. There's also the fact that Vettul started feeling him up first. And then Vettul gets upset because she can tell he cares more about defending himself, and then the Doctor appears by communication screen and disapproves too...
 * Deconstructed in The Sisterhood of the Traveling Pants by Lena: She dashes into her house, jeans inside-out, sweaty and disheveled, and her family believes she's either had sex or has been raped. The truth is, a Love Interest has just seen her naked by accident and she ran away in embarassment.
 * In the Confessions of Georgia Nicolson series, Georgia trips over while kissing a boy outdoors at a party, causing her short skirt to ride up. When her crush Robbie and rival Lindsay walk by, they then believe she was going much further with the other boy than she really did.

Live-Action TV

 * Averted in one episode of Better Off Ted. Lem carefully folds his clothing before having sex with a hot lawyer on company time.
 * Averted to the extreme in the Star Trek TNG episode "The Emissary". Worf and K'Ehler engage in a combat exercise program... then they engage each other. Cut to commercial break. When we return, both characters are completely dressed -- without so much as a wrinkled wardrobe. K'Ehler's wistfull line about some calisthenics being better than others is the only verification audience really has as to what just happened. At least in that episode.
 * Played straight in the Star Trek: Deep Space Nine episode "Looking for par'Mach in All the Wrong Places" when Worf and Jadzia Dax stumble into med bay the morning after with considerable Clothing Damage.
 * One episode of Smallville has a Wild Teen Party in Clark's barn, in the aftermath we see halfdressed girl scurrying out of the hay, followed by a similarly disheveled guy.
 * In one episode of Whos the Boss, the big clue was that Mona's sweater was on inside out.
 * Monk: Asked to demonstrate his Sherlock Scan powers to a judge, Monk matter-of-factly states that he knows the judge was having sex with his secretary earlier, because the secretary is missing an earring and she's wearing a man's shirt.
 * Happens often in How I Met Your Mother.
 * In Lilly and Marshal's case, the simultanious-sitting-up-from-floor-with-satiated-smiles-and-slightly-askew-clothing is a bit of a running gag.
 * Once subverted when Barney and Ted's sister trick Ted.

Theater

 * Ado Annie at the end of Oklahoma!. With mussed hair, a contented expression on her face and straw clinging to the back of her dress, it appears that she has resolved her quarrel with Will the Good Bad Girl way.

Web Comics

 * Gunnerkrigg Court does this with Kat's parents when she and Annie walk in on them both. Ten minutes later and things would have been awkward indeed.
 * After Helen and Dave first have sex in Narbonic, Mell and Artie return to finds Helen wearing Dave's flannel and Dave in a lab coat.
 * It has been stated by Word of God on the El Goonish Shive forum that something happened, or was about to happen between Tedd and Grace before Sarah rang at his door, but it's a mystery how far they went and how far they planned to go. Tedd is shown adjusting his clothes on his way to answer the door.

Western Animation

 * The Simpsons
 * In episode "22 Short Films About Springfield", Apu has a liaison with a woman in a pool changing room and comes out with his shirt on backwards and his Kwik-E-Mart smock inside out.
 * Also, in "Regarding Margie", Skinner and Edna are seen with ragged clothes on after sex inside a miniature golf castle.