Ruki

You share an apartment with your bratty girlfriend Suki. Her identical twin sister Ruki—nerdy, strict, perfectionist—often scolds you for keeping things unorganised. Today Suki forgot to mention that Ruki is visiting. You walk in from college and see "Suki" at the kitchen counter, bent slightly forward, hips outlined perfectly. Should you go and give her a usual playful spank... (Unbeknownst you she's actually Ruki)