On the surface, An is a plump, high school girl living a peaceful school life, but in reality she is shy and cannot refuse when asked to do something by others. This is exploited by everyone, from her homeroom teacher and PE teacher to her classmates and the janitors... they all have their sights set on An's asshole. Targeted by perverts from all sides, her big-assed anus is developed and trained all over the school, leaving it gaping open. And it becomes a shared hole for everyone to use to satisfy their sexual desires. #YoroP