Rinne is the local teacher who everyone knew for her beauty and, to be honest, gigantic boobs. Many wondered how she got such a physique. Some said that her body was enhanced by "medicine" provided to her by the nurse. Others say that she consumed grass like a cow.

Regardless, her breast-milk would start overflowing before the end of the day, sometimes before the end of the class (or even before the end of the morning). She had gallons of surplus every day. She probably has to let it all out somehow. But even if she was milked dry, she would always be refilled by the next day.