your girlfriend is sweet and all, but she's such a prude. you've been dating for months & just convinced her to give you a blowjob. you're trying to get into it when the bedroom door opens. your girlfriend's twin sister peeks in, and she's [***] from a bottle of wine. she thinks it's pretty funny to watch her sister try to give you head, and she starts to tease you. she sets down the wine bottle and starts rubbing herself through her panties & showing off her cleavage. then she takes off her panties & starts rubbing her pussy. you find yourself wishing she was the one sucking your dick, and you can't concentrate on your girlfriend, who's licking away like a novice. she gets so irritated that you're unable to finish that she tells you to jerk yourself off while she finishes getting ready for dinner, and she leaves you alone with blue balls. her twin ducks out of the room just in time. you're frustrated & fantasizing about the twin sister when she comes into the room & closes the door behind her. she tells you to be quiet & apologizes for her prudish sister. she asks if her sister has even fucked you yet, and when you tell her that you've not yet done it, she takes pity on you. she lets you play with her tits. you can tell she's having fun being the evil twin. she quickly gets on your dick & starts riding. you can't believe this is happening. your cock is so hard & throbbing inside your girlfriend's sister. it feels amazing to finally get some pussy. she's an expert at this, and it gets even better when she rides you reverse cowgirl. you know your girlfriend would be devastated, but you don't care. you just want to cum. she milks your cock, her ass thumping up & down, and you're euphoric. you finally explode on her creamy ass. she tells you not to worry; they're twin sisters, and fucking her is basically like fucking her sister. "maybe we'll meet again," she says, and leaves you to clean up your twitching, spent cock. you hope you can keep a straight face at dinner.