A younger sister with overgrown H-cup breasts, 'China', is raped by her perverted older brother. My brother has sexual feelings for his girlfriend's younger sister.One day, when her classmate came to deliver a notebook, he mistook her for her boyfriend and raped her younger sister out of jealousy...and from that day on, he used sex toys every day. He continues to be raped as a man. Eventually, her younger sister, who was trained by a super masochist, became a lewd woman who became obedient to her older brother and begged for his erect penis...