[This was a custom request] You overhear your girlfriend's little sister on the phone in her bedroom so you decide to listen in, and overhear her talking about how she let a guy piss on her the other day (and she liked it!). You're taken aback and undeniably hard when she catches you listening in. She scolds you and calls you a perv for listening to her dirty conversation but then asks you if you've ever tried watersports. You say no but you've always wanted to... she knocks you back immediately - telling you you're way too old for her AND you're her sister's boyfriend. But you're not taking no for an answer. You start fucking her hard while she asks you to stop and tells you how wrong this is but you don't care. You're so turned on by how much of a little slut she is. You start to push into her ass while she whimpers and tells you she's never had anal before. You're taking her anal virginity! When you slide out of her ass and back into her pussy she's repulsed and begs you to stop - she doesn't want her pussy to get all dirty with her filthy little arse. You tease her even more by making her smell your hard cock right from her arsehole before turning her onto all fours and fucking her hard from behind until you fill up her tiny pussy. When you cum, however, her attitude seems to change. She tells you how full and warm she feels and thinks maybe you shouldn't stop after all. She begs you to keep fucking her holes and lets you use both one after another - switching holes between strokes. You've turned her from a piss slut into an ass to pussy slut. But she still wants to be a good girl and piss on your cock like you'd initially asked her to. Her hot, golden nectar runs all over your cock and she uses it to lubricate her holes so that you can keep on switching between them while you're both covered in her pee. This is when you realise *just* how much of a dirty slut she really is. She admits that the reason she wanted to try piss play is because she caught her Daddy pissing on her Mummy in the shower and it really turned her on. She starts telling you her sordid secrets of how much she would love to let her Daddy fuck and piss all over her while you keep fucking her holes. She cums SO hard that her body is trembling for almost a minute and then she begs you to cum in her ass so that both of her holes are filled. As you slide out of her used hole, she whispers that you will probably be visiting her room a lot more than her sister's from now on.