After being teased and retaliated by pinching her nipples, her nipples overdid the orgasm, causing her older sister to become damaged. (Hakkari Mai, CAWD-515)

My younger brother was giggling and touching my nipples, which made me very uncomfortable... Although I reminded him, "I'm not a girl, don't touch me," I was also touching my nipples and masturbating at the time, and my brother saw me, which led to everything. "You always make fun of me, and now you're playing with my nipples too!" From that day on, my younger brother explored my nipples every day. As the number of times they were rubbed increased, my nipples gradually became as sensitive as my clitoris, and eventually I became their slave.