Pittosporum

Hisaya Yano has trouble with his roommate, Sono Odajima, at the boarding school. He breaks curfew and brings female students into the boy's dormitories. Sono is having intimate relations when Hisaya walks in and is left confused and aroused. Sono forcefully helps him deal with his erection. Made fun of for being "a serious model student," but in fact he finds himself in a jumble of romantic feelings that he can't tell anyone about, combined with his emotional trauma. (Source: Bookwalker)