One day during college, a man who passed out at a drinking party woke up in the room of his senior, Kokonoi. After discovering her secret hobby of "nipple-growing masturbation," the man entered into a relationship with her that they could tell no one about. Time passed, and the man ended up working at the same company as Kokonoi. The two continued their secret affair. Her nipples, developed to be even more sensitive than during her student days, have now become pleasure organs that surpass even the clitoris! Furthermore, Kokonoi began "growing" the man's nipples just as she did her own. The man goes crazy for a type of pleasure completely different from that of his cock. And seeing him like that makes her wet. This is the ultimate culmination of a woman's terrifying record of perversely pursuing the growth of nipples.