To counter back pain, Yuu exercises using a balance ball given by her son. At that moment, she loses her balance and ends up on top of him. Her sweaty body makes her son feel like a woman, causing him to flee in embarrassment. Later, her husband returns and says, 'You're so sexy,' as he embraces Yuu. The long-awaited marital act felt good, but Yuu's body craved more. Since then, Yuu has started masturbating. Seeing this, her son becomes excited and clings to her…
