Where it happened: her house
My girlfriend called to ask if I would come over and watch some movies. Her parents were gone for the weekend . I showed up at her house , her younger sister let me in. We started watching a movie . Her sister said she was going to bed after the first movie . My girlfriend got up and went to the garage and came back with some beers.We drank a few beers while watching a couple movies . We did some kissing and heavy petting . Around 1:00 in the morning she said she was tired and going to bed . She told I could sleep on the couch . I fell asleep ,a couple hours later I awoke when a hand slid into my shorts and started stroking my cock . I reached in the dark and felt her breast . I slid my hands into her night gown and fondled her bare breast . She moved down and pulled my shorts down and started sucking my cock . After a few minutes she got up and pulled her panties off and climbed on top of me . She grabbed my cock and lowered herself onto me . My cock felt her moist cunt ,I almost came . She took my cock all the way in and laid on top of me and started kissing me while pumping my cock . We started fucking fast I knew I would not last much longer . As I was shooting my cum into her tight pussy a light came on . It was my girlfriend .I was screwing her sister .Her sister told her he’s not a virgin any more.