My friend's wife is a lewd tutor

Kato and Matsuda have failed their university entrance exams many times. In order to pass the exam, he asks his friend's wife, Akari, to tutor him. However, due to her bewitching atmosphere and obscene body, I can't concentrate on studying at all. Akari can't help but satisfy Kato's sexual desires, saying, ``If he'll focus on his studies,'' but Matsuda spies on Kato as they wash each other's bodies in the bath. Akari's weakness is seized and Matsuda forces her to masturbate and plays with her body.