[Doushoku (Sirofugu)] I Was Seduced by My Girlfriend’s Sister

A nervous young man stops by to see his girlfriend, only for her teasing older sister to corner him instead, asking whether he and Ami have gone all the way before wrapping her fingers around him and calling him a liar when he insists nothing has happened. Stammering that she's his girlfriend's sister, he can barely resist as she coos over his inexperience, teases that he didn't put up much of a fight, and pushes him down to prove who's really in control. With her heavy breasts pressing against him and a wicked smile, she makes it clear he doesn't get to decide when this ends—and that his first time won't be with the girl he came to see.