A Tail of Two Sisters

Charm Point 1: Sister's Rondo | A Tail of Two Sisters | Charm Point 1 ~シスターズ輪舞~

Two sisters attend the same college, one as a teacher and one as a student. Both of them, however, date college boys the same age. The younger sister has a big problem, because her boyfriend never seems ready to satisfy her. Her older sister`s trouble is just the opposite! (Source: AniDB)