My friend's wife is a lewd private tutor

Imaoka and Yokoyama are taught how to study by their friend's wife, Ayumi, in order to obtain a license as an administrative scrivener. Perhaps because she is a friend's wife, she is misled by Ayumi's erotic pheromones. Now that she reaches her limit of patience, she begs Ayumi, "If sex is bad, at least just go with it!" and decides to have her cum in her mouth. Later, when Yokoyama learns about this, she is unable to concentrate on her studies, Ayumi gives her a sexy class, saying, "I understand. I'll help you feel refreshed and concentrate on your studies."