When I met my girlfriend's younger sister for the first time, she was a cheerful girl who was active in a club. I was interested in her and had a sexual desire for her because she didn't have a boyfriend and was focused on her club activities. It was time to try out the aphrodisiac I had been collecting in secret from my girlfriend...! Or so I thought. I rubbed the aphrodisiac on my girlfriend's sleeping sister's nipples and kneaded her nipples, and she immediately had her first orgasm. From that day on, I made her take the aphrodisiac when she wasn't looking and had sex with her! I made her so sensitive that she had a nipple orgasm and peed herself!