Boin is a franchise that has 2 adult themed OVA series.
Produced by Milky and directed by Shigeki Awai, it follows the sexual adventures of Daisuke, a teacher, who helps his students "role play."
A sequel of Boin that is directed by Kimisuke Murayama. It is about Daisuke and his students who having vacation at a tropical island. Each episode is episodic, meaning they are stand alone, since one character remain a virgin for two episodes.