Wincest is best cest in Revolutionary Girl Utena it seems.
"Previously, we looked at the second arc of Revolutionary Girl Utena, The Black Rose Saga, and talked about many of the elements of the series, such as recycled animation and wincest, that made it quite an interesting watch. As a basic rundown of the series if you’re not familiar with it already, Revolutionary Girl Utena is a series about a noblesse academy where the students live on campus and get into all kinds of drama. The main focus of the series is the character Utena and the mysterious dueling club that has people fighting for the power for the revolution or something. So far within the story, Utena has obtained some kind of Stand-like Prince which assists her in her finishing move, as well as this dark-skinned girl that may or may not be in a physical relationship with her brother." - Attack On Gaming