My sister, who cared about me and volunteered to be my private tutor, was deeply worried about my poor grades. She told me, "I'll do anything for you if you get a perfect score," so I started studying hard. As a result, she transformed into my personal reverse bunny slave, reluctantly serving me by straddling my cock and following my commands for sex. She bounced up and down wildly, climaxing repeatedly. Gradually, she became obedient, her face melting with pleasure, and began enthusiastically giving blowjobs and titty fucks. My ideal training was complete, and during these three days while our parents were away, I enjoyed creampie after creampie with my onahole bunny sister.