I unexpectedly walk in on my stepsister who is already in a dogstyle position, tempting me with her butt touch

I was in a rush to get to work, when I accidentally walked in on my stepsister in a rather compromising position. There she was, on all fours, her luscious ass beckoning me irresistibly. I couldn't help but reach out and give her butt a playful little pat, a tease that made her moan with desire. I knew I had to take advantage of this unexpected opportunity. I unzipped my pants, revealing my throbbing cock. She eagerly took it in her mouth, sucking it with such enthusiasm that I nearly lost control. But I had to maintain my composure, because my mother-in-law might walk in at any moment. I took her from behind, thrusting into her with the same intensity that she had shown me earlier. The sight of her beautiful ass bouncing as I pounded her was too much to resist, and I filled her with my hot load.