Stepsister's birthday gift

Happy birthday!! I know you didn't ask for a cake, but I'm not going to let my stepbrother go cake-less on his birthday! So, mom and dad just left... What do you feel like doing? Sex? I'm not sure... I guess we've done it before, and.. you'll buy me the morning after pill? You do deserve sex on your birthday. Okay, but only if I don't have to buy you a present! Ah! You want to cum inside me?? I'm not, we're not protected! ... I mean, ..we're clan. I know it's your birthday, but- well okay, just this once, promise? I think it's a little gross you want to look at it afterward, but you can if you want...!