You're gaming on your PC when you feel something moving by your legs, and spot your annoying little sister crouched under your desk, trying to gain access to your boxers! You ask her what the hell she's doing and she whines and begs for you to just let her suck your cock, she won't bother you and she'll stay quiet so you can keep gaming with your friends! You tell her no and accuse her of being a little slut, but she insists that it's a real medical issue - mum and dad took her to see a doctor who says she has an oral fixation, so it's not her fault, she really needs it! You tell her to go find someone else's cock to suck but she reminds you that she can't, she's grounded for exactly that reason - your parents caught her sneaking out and sucking random boys' cocks, so now she's not allowed out any more! She begs you to just be a nice brother and let her do it, and besides, it's not like you won't enjoy it! You finally give in, reminding her to stay quiet so your friends don't hear her over your mic, and she gleefully thanks you and takes out your cock! She begins happily licking and sucking it as you try to concentrate on gaming, but she struggles to contain her noises of enjoyment and you keep having to remind her to keep it down! After a while you warn her that you need to cum, which makes her mad! She tells you that she's not had nearly enough time sucking your cock yet, and tells you to hold it in! You try to hold off your cum for a few more minutes but then have to tell her that you really can't hold it anymore; if she keeps sucking it, you're gonna cum. Your sister is annoyed but you sigh and promise her that you'll be ready to go again after like half an hour's rest, which cheers her up slightly! She sucks you fast until you cum down her throat, then insists that she'll just stay her under the desk playing with your cock until it can cum again!
Your annoying little sister is back at it again, begging for cock in her mouth! You're trying to relax and play Mario Kart but she just will not leave you alone, reminding you that your parents told you to help your sister out so she gets what she needs at home and doesn't go out looking for it in the streets! You finally relent and allow her to start sucking your cock, admonishing her when she gets too noisy and enthusiastic as you try to concentrate on your game. As your sister sucks and plays with your cock she says that your mom told her you got a girlfriend recently! Your sister teases you about your new girlfriend and asks if she's sucked your cock yet, and when you admit that you haven't got that far yet she says she bets that she's better at it than your girlfriend! And what's more, when you finally do get your dick sucked by your gf, she bets you end up just thinking about your sister! You tell your sister off for being gross and annoying, but she just giggles and continues sucking you off, waving her feet in the air behind her as she bobs up and down. After a while she's really getting into it and removes her sweatshirt to fondle her own breasts, even pulling her top down to expose her tits. You're shocked and tell her to put them away, to which she responds by teasing you for being so weird over seeing her tits, when she's literally been sucking your cock for month's now! She keeps her tits out as she sucks your cock, and you warn her that you're suddenly really close! Your sister laughs at you and says it was clearly seeing her breasts that's got you so close to the edge currently, and calls you a pervert for needing to cum over your sister's tits! She bends down again and sucks you off quickly until you flood her mouth with cum, then she goes right back to teasing you about your new girlfriend until you tell her to get out and stop annoying you!