My sister was made a reverse bunny girl slave for 3 days…! (Rin House Rin WAAA-543)

My older sister, who's always kind to her younger brother, good or bad, became my tutor out of concern that I wouldn't do well in school. She said, "If I get a perfect score, I'll do anything for you," so I studied hard... to make her my personal reverse bunny girl! At first, she reluctantly started serving me, but as soon as I ordered her to straddle my penis for sex, she'd writhe and climax non-stop! Gradually, she became more compliant, her face melting... even willingly giving me oral sex and breast sex! I've trained her to my liking! For the past three days, with my parents away, I've been able to ejaculate inside her as I please, using a vibrator on my older sister bunny girl!