It was the last winter of his school life and with entrance exams and graduation edging closer, Nozomu didn’t know what to do. He was told to become independent, but he couldn’t find a suitable place to live by himself. His childhood friend Shiori couldn’t stand watching him in his current state and suggested that he live with her. While he thought that it wouldn’t really make him independent, his parents readily agreed to the idea. Before he knew it, they were living together under the same roof. Their cohabitation was only to last one month. Since it’s only for a short period and she’s his childhood friend, he thought that nothing wrong will happen. However, living together with Shiori revealed to him a side which he hadn’t seen before, and he began to see her as a woman. Where will their relationship end up now that he had begun to have feelings for her? (Source: VNDB)

With his parents abroad and his house in renovation all of a sudden, Kouta Kazama ends up staying at the home of his neighbor, Aki Hayama, sharing a room with her. Being childhood friends, they used to be very close, but now, as a man and woman sleeping together, it might not take too long for them to realize their true feelings for each other. [Written by MAL Rewrite]

Takumi just cannot stop fantasizing about Saki-senpai, her voluptuous body just stands out anywhere. One day she talks to him on the train and they become friends. Whenever he can, Takumi stares at her form, always getting a hard-on. The next day he finds out they have the same fetish… and so the story begins. (Source: AniDB)

Lamenting over what happened to her class and seeing that Naotatsu is the only one having sex with his female classmates, teacher Suomi takes the rest of her male students to an exclusive swingers area of the beach. Along with some of her foreign female friends, Suomi starts teaching her students a private lesson. [Written by MAL Rewrite]

Led by their foreign female teacher, Suomi, the students of a certain high school set out on a trip to the Yarimoku nudist beach. There is only one rule the students must follow: it is forbidden to have erections. Hoping to create bonds between her students, Suomi pairs the female students with those who need to relieve their erections. Due to the visual spectacle provided by his classmates, Naotatsu Nagato is the first and only to break his teacher’s rule. However, Naotatsu’s seemingly insatiable lust proves to be problematic for his female classmates. [Written by MAL Rewrite]

Animated adaptation from the game by the same name.

Kaede is the student council president and is also twin sisters with Suzu. Both are childhood friends with Hayato, of which all three are part of the student council. Through their time together, Kaede and Suzu both both fell in love with Hayato. Both try to compete for Hayato’s love and sexual favor.