My girlfriend's sister was lying in bed at our place one night after going out. As she stayed the night, my girlfriend was downstairs watching TV, and her sister was having a little play under the covers. Knowing that the bedroom door does not shut properly, I thought I'd take a peak. It was amazing. The noises she was making were wild. Actually, the noises I was making playing with myself outside were pretty loud, too. I donít think she saw me, but I canít stop getting dirty thoughts in my head about her. It was fantastic. I want to shag her brains out.