继妹决定给男友惊喜，但继兄先干了她的大屁股

I'm dressed as a teacher, on a phone call with my friend, I tell her that I want to surprise my boyfriend who is coming back from a trip, I want to lose my ass virginity to him, and I'm very anxious, he's going to come here to my house without my parents and my stepbrother knowing, I also tell him that I just finished teaching a class so I have to get ready for when he arrives and I hang up the phone. I look back and see my stepbrother staring at me, I'm disconcerted but I don't think he notices and I ask him what he's doing here, and he wants to tell our parents and so I ask him if it can be our secret, and then he tells me that only on one condition, if he eats my ass first, I can't believe this is happening because I'm his stepsister, how can he want this? But he reminds me that I'm his stepsister, and it's either that or tell our parents, and I understand that we're stepbrothers and I end up accepting the proposal, and I start by taking off his pants and sucking his cock.