Due to censorships, anime has a funny way of implying a scene where the characters may have sexual intercourse. It happens in manga, too.
*Spoiler alert! Read at your own risk.
Put the reasons on the character page on this concept page if it is not on the episode or volume page. List the franchise, anime, or manga in alphabetical order.
Just follow the example below and link the episode and image here.
In episode 9 "White," Aoi and Kaoru have a nice date in China Town and spend the night alone in a hotel room. After obtaining Miyabi's permission to spend the night at the hotel (Kaoru calls Miyabi), Kaoru tells Aoi that he always thinks about her happiness, and the two share a passionate kiss while the camera moves away from the two love birds to the city lights. It is possible that the two had sex or not.
In the third season episode "The Southern Raiders", Zuko is trying to find Sokka and ran into a very flustered Suki who rushes off. Zuko enters Sokka's tent to find him without pants and laying on the floor surrounded in flowers and candies, saying "Well, hellooo..." in a suggestive tone before realizing who it was. The two briefly chat before Sokka rushes Zuko out and tries finding Suki. The following day, we see Sokka fiddling with a flower necklace and he literally exclaims, "I got lei'd".
In episode 4 "Are you two going out", Souichiro Tanaka and Kanako Ohno both like each other, but they both are afraid to confess their love for each other. When Saki tells Kanako to cosplay, Kanako decides to cosplay as a hentai character. Meanwhile, Tanaka talks to his buddy (big guy working on the computers) about him being weak in front of Kanako. Despite Tanaka's friend's fear of asking a girl, Tanaka heads to Kanako's house. Kanako pressures Tanaka to reveal his hentai games, and she picks one character and makes Tanaka play the game to "beat" scenario. However, Tanaka gives up and confesses his love to her. Kanako tells Tanaka that she will help him be confident by kissing him when she turns the light. After they discover that they both are virgin kissers, Kanako talks to Tanaka if he wants to go a "little further." The two engage and kiss each other with passionate and erotic moans as the viewers see the hentai game case. The erotic moans end with a man who drinks water and moans the same way.
In episode 11, Renji and Chihiro profess their love for one another on the rooptop of their school and embrace one another. The next shot features the clothes of both characters folded neatly and they are shown to be naked lying on the rooftop with Chihiro resting on Renji's chest.
It happens on two different occasions in the anime between Shirou and Saber. On Tohsaka's urgings to replenish Saber's mana in order to defeat Berserker, Shirou has to do the unthinkable to Saber, who he likes. Interestingly, this concept of giving mana through sexual intercourse reflects a Chinese religion and others.
Hints: Saber tells Shirou: "You know my past, and you've entered me so many times."
It happens once in the movie between Shirou and Rin Tohsaka. The same reasons as the anime except Shirou is the one who needs the mana. The scene changes to Shirou who "enters" Rin and sees her memories and flashbacks. Interestingly, Rin hits Shirou for seeing her memories whereas in the visual novel, she hits him for being too "rough."
See movie page.
Clues that suggest the two had pre marital sex:
In the OAD, Drifters of the Dead when Saeko and Takashi are alone after they escaped from the hallucinatory emissions of the hydrangea, Saeko tried to seduce Takashi and confessed her feelings for him, as a result, the two teenagers started kissing and touching each other with passion while the camera slowly moved away as a transition for the next scene. Although it was all a hallucination, it is a clear example of an implied sex scene. Another point, is that the sex scene could be Takashi's imagination or Saeko's imagination due to another scene where Saeko and Rei are kissing each other at sun rise.
Another pair, Saeko and Rei, are found kissing each other. Due to the hydrangea's hallucinogenic properties, the two girls thought that they are having "sex" with Takashi when it turns out they have sex with each other.
While Yukino and Arima are at a bus stop to dry off from a rain shower in episode 18, Arima suggests that the two run to his house since it isn't far from the bus stop. However, the two would be all alone since Arima's aunt and uncle wouldn't be home until later in the evening. The two then exchange blushing faces at one another. Yukino then remarks at how happy her relationship with Arima has developed despite any later difficulties they could possibly face. The scene then changes to a number of still shots that apparently take place in Arima's bedroom as Yukino and Arima kiss one another while sitting on a bed. A white screen then appears with the words "I think I'll go crazy" appearing. Another scene appears with younger versions of Yukino and Arima meeting one another in a grassy field as Arima catches Yukino's hat blown away from her by the wind and the two exchange smiles with one another. The scene changes to apparently occurring later in the evening as you see Yukino and Arima sleeping together in a bed with only their heads and shoulders visible from the sheet covering them.
Note: The Japanese video release includes additional drawn stills taken from the title's manga and some narration from Yukino that further imply that she and Arima might have had intercourse with one another. Shots are shown of their clothes thrown on the floor and there is a still showing Arima on top of Yukino while they are covered up in a sheet, followed by a few up-close shots of their faces and different parts of the bedroom. Yukino's narration includes the mentioned line used from the American video release, as well as a couple moans.
In episode 4, Mayama is accompanying Rika on a trip to Hokkaido as the latter visits where her burnt-down home used to be. The two embrace as Mayama comes to learn that Rika is starting to show signs of moving on from the death of her former lover. The next scene then shows the two sleeping together in a hotel room with only their heads and shoulders visible from the blankets covering them.
In episode 5, Koko and Valmet are sharing a hotel room together with Koko clearly having a bit too much to drink with her drunken behavior and sloppy pouring of wine. Valmet offers to get Koko to bed and taking advantage of the opportunity, a giddy Valmet offers to shower together with Koko and sleep with her in bed afterward, promising to "wipe away [her] exhaustion." As Valmet is about to undress Koko, the scene cuts away to a shower faucet being started up and then a far shot of the hotel they are staying at as the viewer hears Valmet's giddy declaration.
Once Koshiro and Nanoka come to terms with their feelings for one another in episode 12, they kiss. The scene then changes to a camera shot of the top of a table with an apple on it as the two siblings talk of what they are about to do and Koshiro asks if Nanoka has any regrets. Another camera shot occurs which implies to take place later in the evening where we get a close shot of Koshiro and Nanoka lying together, having nothing but a sheet covering them.
Masayoshi discovers his best friend, Eutus, and his crush, Mune Mune, shoes on the porch, and he hears something wrong. After that, Masayoshi takes up drinking since his heart is shattered. Masayoshi tries to kill Eutus, but he knows what Masayoshi is up to so he vanishes from Masayoshi's eyes.
See episode 7.
At the end of episode 4, Sorata promises to take Mei out on a date as a reward for contributing to their latest theft. For their "date", Mei and Sorata are in the latter's bedroom with both in states of undress with Sorata in a T-shirt and boxers and Mei in some negligee. The two get on Sorata's bed where Sorata lies down and much of the lower half of his body is strategically obscured with a chair from a far camera shot. We then get a close camera shot of Mei's head and shoulders as she is about to go down with Sorata saying she's "so excited". The camera then goes back to a visibly flustered Sorata with the mentioned strategic shot and then the camera cuts to a picture of Mei and Sorata as we hear meowing and howling sounds from the two as the episode ends.
In episode 22, Yukino confronts Shizuru about her apparent actions with Natsuki. The scene then changes to a flashback where Yukino is using her Child to spy on Shizuru and Natsuki in silhouette behind a screen window. While Natsuki lies sleeping in a futon, Shizuru disrobes from her kimono and implied to be nude as she lies alongside Natsuki. While there is nothing further shown of what happens, Shizuru's apparent actions are enough to disgust Yukino and shock Natsuki when she overhears what is going on.
Before Travis Touchdown began to break into Pizza Batt's tower, he found Sylvia Christel on his doorstep while calling her about the final mission. After the two kiss, they walk back in the motel and the camera zooms back into the motel's whole view as said motel shakes like an earthquake. A number of seconds later, Travis comes out of his motel home shirtless. After the scene and before heading to the final boss battle's setting, Sylvia can be seen still in Travis's bed whenever the player moves around Travis's home.
In a flashback of Ritsu's high school days, Ritsu remembers when he had confessed his love to his senpai, Saga, and they had started dating (The dating was implied and not directly stated). In the flashback there was a scene where his senpai didn't have a shirt on, they were in bed, Ritsu's shirt was unbuttoned completely, a sheet was over them, and they were kissing. Ritsu grips his senpai's hair, and in the next scene they are seen asleep in the same bed until Ritsu snaps out of the flashback scolding himself for thinking about a person whose face he can't even remember.
The inner monologue during the scene may suggest it because Ritsu was being pessimistic at the time saying that it didn't matter if you were hurt a little in love, but he had never tried to fall in love from that day on. The biggest evidence that this scene is most likely implied sex is because the same scene in the manga is an actual sex scene.
See episode 1.
So far it happens once in the manga and not yet in the anime. When Anna tells Yoh that this is the last night that he will spend in her house, she asks Yoh if she can sleep beside him. Yoh says yes.
See volume 9 and the image on this page.
Note: It has been confirmed in episode 25 that Yoh and Anna did not have an implied sex scene in the anime.
The implied sex scene occurs between Majic and Fiena. After they escape from the funeral pyre (where Majic is fully clothed underneath Fiena's ceremonial wolf outfit), the next scene reveals Fiena is standing on a balcony looking out while Majic is sitting on the bed, shirtless. Majic is pulling on his boots (aka The Kirk Maneuver). He then walks up and embraces Fiena from behind.
See episode 6.
The anime has a number of implied scenes among its female cast throughout the show's run. Here are some examples:
In episode 10, Kirito spends the night with Asuna in the same bed. The scene can be debated both ways. Here are the hints for an implied sex scene.
Following a scene where Milly comforts Wolfwood as the latter contemplated over his murder of Zazie the Beast in episode 23, the next scene shows a shirtless Wolfwood smoking by a window with Milly sleeping in bed.