Binetsukko ♭37℃ The Animation (2003) +18

Original title: 微熱っ娘 ♭[フラット]37℃ THE ANIMATION

Inuhiko has blackmailed a female student, Kagido, with some embarrassing pictures, making her his sex slave. Kenji, a friend of Inuhiko, also wants a sex slave who happens to be a distant cousin of Kenji's. Together they use the girls whenever they want whether the girls want it or not.