Fuyu is an ordinary housewife raising her teenage son. One day, her son catches her masturbating and takes advantage of the situation to make advances on her. Though she resists at first, insisting they're mother and son, he tells her that if he cums inside her, it would be like cheating. He argues that vaginal sex is out of the question, but anal is not considered incest, and since pregnancy is impossible, he can cum as much as he wants. Yielding to his pleas, Fuyu offers her anus as her son's rock-hard cock relentlessly pounds her backdoor.