Toshio, an unattractive, uncool guy, spends his days masturbating to relieve the loneliness of not having a girlfriend. Worried about Toshio, his stepmother Akari decides to use her own body as a practice dummy to teach him about the female body. With only her knowledge of adult videos, Toshio tries to follow her desires, but Akari patiently teaches him about the female body. Thanks to Akari's sex education, Toshio improves rapidly. And as they make love again and again...