HUNTB-104 "If you teach me how to study, I'll teach you dirty things." A private lesson with exchange conditions between my slutty stepsister whose grades are terrible and me, the studious virgin.

Up until now, my stepsister had never studied at all. One day she suddenly said, 'I'm going to college!' I was asked by my stepmother to teach her, but... this is impossible! She's way too stupid! I quickly gave up on my idiot stepsister. But then she said that if I taught her how to study, she'd teach me dirty things... I'm a studious type who's good at studying, and my stepsister is a slut who's good at sex... Result... it's a win-win equivalent exchange! So we started secret private lessons!