Stepsister walks in on me masturbating in lingerie

I've been living with my step-sister for a while now, and it's been pretty awkward. I can't help but notice her killer curves, especially that big ass she's got. One day, I was feeling extra horny and decided to jack off. Just as I was getting into it, my step-sister walked in on me. At first, she was shocked, but then she got really turned on. She dropped to her knees and started sucking my cock like a pro. I was blown away. We've never even kissed before, but here we were, about to fuck. She bent over and I took her from behind, pounding her tight pussy. Then we switched to missionary, so I could see her beautiful face as I fucked her. After that, we tried doggystyle, and it was even hotter than before. I was amazed by her stamina, and so was she. We finished off with some more blowjobs before we called it a day. It was the hottest sex of my life.