Real slut! I blow my stepsister's boyfriend!

It's been a while since my stepsister made a surprise visit. I see her sooo rarely anyway and was really pleased. Especially when she brought her new boyfriend with her... He looked so good. So we had a really nice evening together and as I didn't want to let them sleep on my uncomfortable sofa, I just invited them into my bed and my sister just said: "It's big enough for the three of us." So we even sleep together in the same bed. I was surprised that she didn't mind at all that her boyfriend and I were almost or completely nude, but her idea in the morning really blew me away. I should just give him a blowjob like that!