Living alone with my sister, my daily routine was suddenly disrupted when she announced a friend was coming over. Thinking it was just a casual visit, I didn't think much of it—until I accidentally caught a close glimpse of her friend changing clothes. Struck by her incredible figure, my heart began to race, only for her to suddenly whisper, "Want to do something dirty?" Before I could react, I nervously nodded, and in an instant, I was kicked down, pinned to the floor. Taking advantage of my sister's absence, she began bullying me, forcibly stripping me naked, hurling insults, and making me ejaculate over and over again against my will.