Our Lady Deigns to Love Sex! / Ojou-sama wa H ga Osuki: The Animation

Before us is the story of two rich sisters: they have everything they could wish for, and a beautiful, richly furnished mansion, and servants ready to do anything for their mistress. However, when it comes to their relationships with guys, that's where the eternal dispute between the sisters begins - who has a better guy and who knows how to please men better. For this, they arrange a sex duel and exchange their boyfriends - the one who makes him cum faster wins...

 Added voice acting by Anistar