My stepsister discovers me masturbating to her panties and vigorously has sex with me until I climax inside her butt

I was in my dorm room, getting ready to attend a study group with my stepsister. I started to feel a bit horny, so I went ahead and began to stroke my cock while fantasizing about my stepsister. Little did I know, my stepsister walked in on me just as I was reaching my climax. She was visibly upset by what she saw and we had a heated conversation about it. However, she was also clearly aroused by the sight of me masturbating while wearing her panties. In a surprising turn of events, she decided to take matters into her own hands and have sex with me. Despite our strict rules against such actions, we both succumbed to our desires and engaged in passionate sex. The intensity of our encounter culminated in a powerful orgasm, which I released inside her butt. This experience was both thrilling and taboo, pushing the boundaries of our relationship and our understanding of sexual norms.