MKON-140 — I Was Feeling Awkward When I Ended Up Alone With My Friend's Little Sister, But It Turned Out She Was A Total Brat! She Called Me A "Loser" And F** Me To Have Sex With Her, Milking Me Dry And Cumming Inside Her. - Karin Kitaoka

Satoru finds himself alone with his younger sister, Karin, at a friend's house. Karin suggests a game where the loser has to do whatever the loser says, and Satoru loses. Karin demands that he become her personal chair. Satoru does as he's told and becomes a chair, and Karin notices his erection, admiring it and berating him. The next day, Karin demands sex from him again, and this time they have sex. He is milked dry and falls into slavery.