Your sister and her boyfriend came home unexpectedly and caught you perusing her panty drawer. He beat the shit out of you, and watching got her so turned on she gave it up to him right then and there. "Serves you right, you perv!"
Your mom has decided to make sure you're a kissless virgin for life. So when she caught you on SC with a girl, she made you invite the girl over for a "pool party" and watch while mommy ruined her for any man ever again