Japan was engulfed in a demographic crisis, forcing the government to implement the “Ikumonogakari” law, which permitted promiscuous sexual interactions among the people. They started doing practical and pedagogical activities on the lessons of sexual life and a partner’s sexual fulfillment. The protagonists are young and inexperienced, so practical exercises will help them to improve their skills.

Yuu Arahama has a girlfriend named Misako Shimizu. She has a great body and loves him greatly. One night, after having sexual intercourse, Misako proposes to Yuu. However, he rejects her proposal, revealing that Misako isn’t his only partner. He has four other partners: Ryouko Yanagi, Kotori Hoshino, Makiko Endou, and Aina Kamishima. Misako makes Yuu call all four of them at once, only to find out that each girl is not aware that Yuu has sexual relationships with the others. Another problem arises when the girls decide to compete with each other so as to determine whom Yuu is going to choose as his wife. However, Yuu is reluctant to marry anyone, fearful of the possibility that he will lose his freedom when he gets married. Now, Yuu has to go through various situations which forces him to go through sexual activities with the girls to sate their lustful desires and settle their feud. [Written by MAL Rewrite]

Seduction and sexuality seem to be in the air, water, or both at the school Joshikousei no Koshitsuki. The institute’s beach volleyball coach got the surprise of his lifetime when the busty and seductive Saori Kiryuu came asking for special training to get over her embarrassment in a swimsuit. Unbeknownst to him, Saori’s sister was watching the entire time, and she wants their sensei for herself. Now he must come to grips with having two very sexually charged young women in his life whilst attempting to maintain his composure as a teacher. He’s not alone in his erotic misadventures, however. The female tennis team feels strong lust towards the male team, the all-girls billiards club wants at the male manga club, and the drama organization is about to engage in a supreme orgy to help their cast members bolster their own sense of self-worth. When it comes to physical pleasure, there’s something new to learn for every one of the students and faculty at this “educational” institute.

Based on the manga by TakayaKi. A collection of short but sweet romantic stories with happy endings.

In a certain normal Japanese high school, there are two peculiar students: a lonesome boy and Shiiba, a mysterious girl. Neither of them have many friends; but unlike the dull and boring boy, Shiiba is beautiful and considered to be in a vastly different league to the other males in school. Therefore, no one has had the courage to ask her out. Nonetheless, it comes as a pleasant surprise to the plain boy when Shiiba invites him to an empty room. Elsewhere in the world, a certain teenager has just returned home from a long day at school. As he approaches his room, however, he hears sounds from a porn video he had once watched. Startled, he charges into his room and finds his younger step-sister, Miku, watching the tapes. It is no surprise to her that teenage boys are interested in these things, but what she does not expect is that she would take an interest in it herself… [Written by MAL Rewrite]

As Yusuke Nakonishi begins his new job at the Best Beauty Body Lingerie Company, little does he know that he’s about to find himself in the center of a ring of business and sexual intrigue. Charged to disrupt and eliminate the cohorts of an opposing faction, Nakonishi thrusts himself on the prowl after three of his sexy co-workers around whom this sex drama spirals. (Source: AniDB)