I massage my stepsister's back and end up having sex with her

I was feeling a bit of a nagging pain in my back, so I decided to give it a little rub. My step-sis happened to be around, and she offered to help me out. At first, I was just going to have her rub my shoulders, but as she started to work her magic, I found myself getting more and more into it. Before I knew it, I was on my knees in front of her, my mouth all over her. It was like I couldn't get enough of her. I could feel her moaning and writhing under me, her hands exploring every inch of my body. It was like we were the only two people in the world. After a bit of a break, I found myself on my back, my legs spread wide open. She climbed on top of me, her body moving in rhythm with mine. It was like we were dancing, our bodies intertwined in a slow, sensual waltz. And when we finally finished, we both breathed a deep sigh of satisfaction.