Keiko, who has been married to a man with a stepson attending a local university for half a year. One day, her stepson Kazuya, who was on vacation, came home... Keiko noticed that Kazuya, who indulged in masturbation many times a day due to his high libido, made her feel a throbbing desire every time she entered his room filled with the smell of a male. At such times, Keiko, whose eyes were captivated by his morning erection while he was asleep, couldn't help but reach out her hand. Unable to resist, she let him ejaculate with her hand, but the super virile Kazuya wasn't satisfied with just that, and he begged her to let him ejaculate many times...