Pervert! Stepsister mistaken for girlfriend!

I didn't think it would work. I wanted to see if my stepsister's boyfriend would notice that I was naked under the covers instead of her and it actually worked. Oh my god....er really didn't notice. Since we have the same tattoos on our ankles it was a bit difficult but actually our pussies don't look quite the same. HAHA! It was so funny, I had to hold myself back so it wouldn't be immediately obvious. He fucked me hard, I was always horny for his cock and only after he pulled the cloth away, he recognised me. At first he didn't want to go on but then I managed to convince him. He fucked my tight hole even harder than I could persuade him and then shot his whole load into the rubber, which I then sucked out with pleasure. OMG....my stepsister must never know!