When I met my girlfriend's younger sister for the first time, she was an introverted and shy beautiful girl. I was interested in and had sexual desire for my younger sister, who was the complete opposite of my outgoing and experienced girlfriend, and was pure and innocent and had never known a man. And I couldn't help but touch her unexplored nipples... At first, my sister refused the sudden nipple play, but when I relentlessly kneaded and twisted her nipples, she had her first orgasm. I made her develop a nipple orgasm and premature ejaculation constitution even with the slightest stimulation, and had a lot of nipple sex!