Yuriko witnesses her son masturbating. She can't get her mind off her grown-up son's rock hard cock, so she starts masturbating in her bedroom. Her son feels something's off when he hears some noises in the bedroom and peeks in. He also witnesses his mother masturbating. When her son says he can't take it anymore, his mother accepts, saying "Just once." Not content with just one time, her son begs for anal sex, saying "This is a good place, isn't it?", and his mother also accepts her son.