Dai, who is ignorant about sex, doesn't know how to release his erect penis and spends his days in agony. At that time, he decides to ask for advice from his friend's mother, Momoko, who is always kind to him... Momoko, who knows his troubles, is confused but secretly teaches him about sex. Then, Dai loses himself in the excitement and pleasure he has never experienced before and pushes Momoko down with too much momentum. Momoko swings her hips like a monkey and climaxes repeatedly as his penis stimulates the depths of her vagina...