Shakkin Shimai...

Paid & Laid

Based on the adult game by Selen. Hiroyuki is a high school student. He happens to know that Kaho, his classmate, and Kasumi, his classroom teacher, have a lot of outstanding debts their deceased father left. He feels sorry and offers Kasumi to lend some money, but she refuses it. Her attitude makes him mad and he decides to make them his sex slaves... (Source...