I really needed to use the bathroom. My stepsister Spencer, was using it at the moment. I waited 10 minutes but I couldn't hold it any longer. I call out to her to see if it was ok, she said it was fine, that she was in a towel. Entering the bathroom, I gaze my eyes upon her slim shoulders and down her towel. I apologize for the inconvenience. She doesn't pay much mind to it. I sat down on the toilet and look over to her when suddenly her towel drops to the floor, her body so tight and lean, her butt tiny and fit. She let out a huge gasp, shock and embarrassment on her face. She asks me the very obvious question "Did you see anything?" I wasn't going to lie but I twisted it into a compliment. Spencer instantly blushes, now feeling very good about herself. She then asked if I wouldn't mind checking out her gym results. In this moment, my face felt flushed, I knew this scenario from all the porn I have ever watched, I felt I already knew where this was leading up to. She's my actual stepsister though but how could I say no. "Sure," I said and her towel drops again. She flexes and shows off her body, nervous and horny I try to keep it friendly and playful. Complimenting her, while also poking fun at her petite figure. Then it happens, she asks for a favor. I knew where this was heading, my cock already feeling harder. Fear of being caught running through my head. What if it's awkward tomorrow? She seduces and lures me into the bedroom, drops to her knees... I won't reveal everything, she's my stepsister after all but lets just say there was lots of oral, doggy and missionary and I had to take it very slow with her. Her pussy was super tight and my cock is very thick. To see everything that happens you can view my memory fragment and relive my experience.