My best friend (a virgin) came over to my house with his girlfriend! What's more, she's a slut and isn't satisfied with my friend's immature sex. She showed me her panties when my friend wasn't looking and played with my crotch with her feet, seducing me! I thought to myself, "How frustrated are you?" but I couldn't resist the temptation and had sex with her. But at the very least, I tried to do it outside for the sake of our friendship, and she locked me in a crab hold! Damn! If I end up cumming inside her, I'll be a real scumbag.