My girlfriend invited me to her house where I found her sister alone. So I sat there waiting for my girlfriend while her unbelievable sexy sister was sitting next to me . A few  moments later she whispered to me  we should have sex while my sister isn't home . I immediately got up and turned around to head back to my car. I found my girlfriend standing by the door, she hugged me and said ' you've won my trust' . Moral of the story : Always keep your condoms in the car .