Yui, a mother, lives with her only son, Takahide, waiting for her husband to leave for work. She can't help but feel frustrated after living away from her husband for more than three months, and her body naturally starts to play with her crotch... So she invites her son's friend, Tomoma, over and prepares him to suit her tastes, releasing her pent-up sexual desire, but she isn't satisfied with just devouring carnal desires. One day, when Yui sees Takahide's penis, she can't hide her excitement at the sight of her virgin son's fully grown penis...