Bijin katei kyôshi: Fukuyoka na tanima (2002)

Erika, a female college student, works part-time as a nude model. One day, she steps in for a friend to tutor Masato, the son of the popular actor Kasuga. Masato becomes intrigued by Erika’s beautiful physique. She proposes a deal: he can touch her body as his grades improve, and if he reaches the level required to pass the entrance exam for a top-tier university, she will sleep with him...