18+ S-kke Mama no Kibishii Kozukuri Seikyouiku

High school student Kouji finds himself attracted to older women. Sadly for him, though, he attends an all boys' school where the female teachers are old and ugly; it also doesn't help that his 38-year-old mother is beautiful, with a great body to boot. As a result, Kouji often finds himself thinking about her.

One day, when Kouji's report card arrives, his mother discovers that he's gotten a "D" in Health Education. Worried that her son might not be receiving the proper knowledge—or, even worse, that he may become a sex offender in the future—she decides to take matters into her own hands and teach Kouji the ins and outs of intimacy.