In preparation for the pool lessons starting this summer, the school is holding a swimsuit fitting session. Hinano can't afford to buy a new swimsuit, so she wants to get through this summer in a small one... But then her perverted gym teacher says, "I'll teach you some secret tricks," and starts playing with her nipples through her swimsuit, forcing her to develop them! Her developing, plump nipples are so sensitive that she arches her back and climaxes! Her small body convulses as he escalates his pranks...