Sae, a mother, headed to the balcony to bring in the laundry, but for some reason she noticed that the door to her son Shinichi's room was open. When she peeked in, she found Shinichi indulging in masturbation. It was a natural thing to do for a boy his age, but she was aroused by the sight of him vigorously playing with his nipples at the same time as his penis. Sae could no longer control her reason...