I get aroused while assisting my naive stepsister with her studies

I was helping my sweet, innocent stepsis with her homework when she caught me rock hard. She knew I had a thing for her, and she couldn\'t resist teasing me by straddling me and riding my throbbing member. It was a wild ride, with her tight, petite body bouncing up and down on my huge cock, driving me to the brink of ecstasy.