Bijo kateikyôshi no tanima lesson.

Mayumi, a university student, takes over a part-time job as a private tutor from her best friend Reiko and heads to the Ishihara household, where father and son live. After passing the interview, she tries her best to tutor her shy son Koji, who is a second-time repeater, but Koji can't help but be distracted by Mayumi's cleavage...