Mamami-chan, the class representative, is a bit of an H girl. During classes, she imagines lewd things or masturbates without getting caught. Even at home, she plays with her nipples. I'm really a bad kid. I wonder if the boys in my class would moan if they played with their nipples like I do? Mamami-chan, who has become interested in boys' nipples, invites Kudo-kun, another class representative, to her house to let him touch her nipples. A secret shared between classmates. Watching a boy feel pleasure from his nipples, Mamami-chan begins to develop a slutty side…
