Yuna, who has recently been sexless and frustrated, finds out that her son's friend Kosuke is masturbating to her, so she secretly snacks on him... Kosuke's cock is so strong that it doesn't die down after one or two ejaculations. At first, Yuna enjoys being fucked almost every day, but gradually she begins to feel her limits. But Kosuke keeps making her cum with all his might, and her body finally screams out in pain...