お兄ちゃん、私みたいなまな板貧乳の妹に足コキされて感じちゃうんだ。変態だね。ド変態★

Yuuichi steals his sister's underwear and is using it to masturbate, until one day she catches him red-handed. She decides to keep it a secret from their parents though, and uses it to blackmail her perverted brother. Now he has no choice but to become his little sister's slave.