Sexfriend

Sexfriend (セックスフレンド, Sekkusufurendo) is a hentai computer game and anime. Sexfriend focuses on the protagonist, Tomohiro Takabe, who has his first sexual encounter in the nurse's office after school with his classmate, Mina Hayase. He eventually desires a real romantic relationship, not just "friends with benefits". Another student, Kaori Nonomiya, sees Takabe and Hayase having sex and runs off disappointed because she loves Takabe. She eventually joins them in a threesome.