Kotaro, who is sensitive about his nipples, tries to overcome this weakness through weight training. However, even as his body becomes stronger, his nipples remain just as sensitive. One day, his mother's friend, Kirami, comes to the house... Kirami, frustrated by her sexless marriage, transforms upon learning Kotaro's erogenous zones and begins to tease his sensitive nipples while no one is looking. Overwhelmed by the sensation of being sucked and licked repeatedly, Kotaro struggles with this new experience but finds himself drawn into her nipple torture...
