Amateur step sister with a big ass gets stuck and I have sex with her

I was always fantasizing about my step sister, her big ass and her big tits were always on my mind. I was walking through the dorms one day when I saw her stuck in the chair, her fat ass bouncing up and down as she tried to get free. I couldn't resist the sight and I just had to have her. I walked over to her and started helping her out of the chair, my hands were all over her chubby body. She was a bit surprised by my sudden advances, but she didn't mind. It was kind of like a forbidden love, her being my step sister, but we both wanted it. We went upstairs to her room and we started to fuck. She was a bit of a surprise, I thought she was just a pretty face, but she was a horny teen with a nice ass. We had sex all around the house, and every time I saw her, I just wanted to fuck her again.