Horny Step-Brother Grants Step-Sister's Birthday Wish with Big Dick Birthday Sex

I was so shocked when I found my step-sister, Natana, alone in her bedroom on her birthday. I just got back from buying her some balloons and a card, she tells me all her friends bailed on her and she is super upset about it. I try to cheer her up but she seems really down, Natana was telling me she was really hoping to have sex on her birthday. In total shock, I tell her that is probably a bad idea but she insists I make her birthday wish. I just wanna make my step-sister happy on her birthday.