Sister's Oral Pleasures ~ Mitarai Family History ~ / Fela Pure: Mitarashi-san Chi no Jijou The Animation

The main character, Mitarai Keiko, is a very strict and responsible student council president, and it's no wonder everyone fears and respects her. But that's one side of her personality; the other is concerned only with her younger brother Noboru's genitals. When she's at home, she never lets his penis out of her mouth for a moment. What incredible perversions is Keiko willing to commit to satisfy her lust?