Satsuki is happy that her daughter has a boyfriend. One day, when she returned home after forgetting something, her daughter had brought her boyfriend, Okamoto. When he peeks into her room to check on her, the two find it awkward as their first sex doesn't go well. Satsuki, who wants to support her daughter's love life, decides to become Okamoto's training ground so that she can gain confidence. However, Satsuki's plump body excites Okamoto more than he imagined. It was supposed to be just bare thighs