Brea is approaching her older experienced step-sister Roxy to ask her for some advice about sex. Brea asks her about some of the stuff she has done with guys, Roxy avoids giving too many specifics to protect what she thinks is her innocent step-sister. Brea tells Roxy that her boyfriend and her have been going out a while and wants to start being sexual with him. The problem is that her boyfriend is really religious and thinks its wrong to have sex before marriage, she hasn’t even seen his penis or any penis before. However, Brea says her boyfriend has a loophole, anal doesn’t count so they could do that instead and it wouldn’t go against his religion. Roxy is very sceptical and tells Brea that her boyfriend is being dishonest & just trying to take advantage of her, but Brea won’t hear any of it, she says that he loves her and would never do anything like that. Roxy tries to talk some sense into her, but Brea won’t be swayed. Brea asks Roxy if she has ever done anal as she is nervous about it because she heard that it can be kind of rough first time round. She asks Roxy for some tips, she is hesitant but figures that it is best to help Brea instead of letting her go in blind. She has Brea take off her clothes and panties, telling her to turn around. Roxy fingers her asshole so she will have an idea of how it will feel with a penis as Brea moans. Roxy is trying to be gentle and asking if Brea has had enough. Brea says that she thinks she needs to try something more, her boyfriend is always talking about how big his dick is. Roxy says that he is probably exaggerating about his size like most guys do, Brea insists that he would never lie to her. Roxy says that they have nothing bigger to practice with, Brea rather timidly suggests that they do their step-brother. Roxy says that is inappropriate and they can't do that. Brea acts upset and Roxy relents and agrees. Calling their step-brother into the room to explain the situation to him. He takes little convincing before he takes his dick out. Roxy is shocked by the size, but hides her reaction from Brea. Brea is looking at the dick with great interest, asking if it's big or not. Roxy secretly signals to her step-brother to play along and says that actually it’s just a little below average. Brea says it looks pretty big to her but Roxy would know better and she wonders how big her boyfriends must be if his is so big. Roxy tells Brea to go her bedroom & get the lube. When she leaves, Roxy looks at her step-brother and tells him that that’s the biggest cock she has ever seen. She explains how she lied to Brea was so that she would try anal with their step-brother’s cock & it would be way too big putting her off the idea of trying with her boyfriend. The step-brother is not terribly concerned about the details, he is in. Brea returns very giddy & Roxy is lubing up their step-brother’s cock. Brea gets into position to take his cock, he starts to push into her asshole. Brea struggles alot but eventually gets the cock part of the way in. Tells her step-brother to go slowly in and out. But she says that she can’t handle anymore & tells her step-brother to pull out. Brea says she’s not sure if she will be able to go through with it with her boyfriend as he's supposed to be way bigger. Roxy is happy to hear this. She looks sheepishly at Roxy as she says maybe you could show me how to do better, after all she has probably already had way bigger. Roxy is lost for words, she doesn’t want Brea to know about her plan to trick her. She tries making excuses, but their step-brother says it's a good idea. Roxy glares at him, she is nervous because it’s the biggest cock she has ever taken. Brea asks why she is hesitant, Roxy makes an excuse and tries again to get out of it but it’s no use. Her step-brother starts to push his cock into her asshole, she is struggling even more than Brea was. Brea tries to encourage her and is a bit confused as to why she is having so much trouble given that Roxy is supposed to have plenty of experience at this. Roxy gets the cock as far in as Brea had and she yells as she tries to get off, saying that the cock is too big. Brea is shocked and angry, she yells at Roxy saying how could she lie to her, she was trying to get her help and she tried to trick her. Roxy is trying to tell her it was for her own good, that she was trying to protect her. Brea tells her to fuck their step-brother’s cock until he cums in her ass balls deep, taunting her all the way, until Roxy has a moaning painful anal orgasm, filling her ass with cum then pulling out to gape it open with cum dripping out.