Your little sis confides in you that she's the only girl at school who isn't doing sex stuff. "I don't know if I'm ready yet but I'd at least like to see a boy's dick... maybe I could see yours?" you're surprised, but waste no time whipping it out for her. She asks you why it's hard; you encourage her to give it a taste. Her curiosity outweighs her hesitance and she begins to lick you "like a lollipop" giggling about about your parents would say if they walked in. "Oh right, I promised you could see mine too..." she lays back and spreads her perfect little legs to display her tight pink virgin hole. Your cock is throbbing, you want to fuck your step-sister so bad. She can tell you're turned on, and agrees to let you slide it up and down her wet little slit "BUT THAT'S IT! We're step-brother and step-sister... we definitely can't have sex!" She's doesn't want to lose her virginity, so you convince her to let you put in "just the tip" because it doesn't really count unless the whole dick goes in ;) one thing leads to another, and it accidentally slips in. She's upset, but realizes there's no point not having sex if she's already lost her virginity. She rides you cowgirl and reverse cowgirl. You can't control yourself, holding her hips down to creampie your very own step-sister's virgin pussy.