"You've Never Seen a Pussy Before?!" - I'm His Birthday Sex Doll

My stepbrother has no friends and no girlfriend, but it doesn't matter. I'm going to make sure he has the best birthday ever, and he won't need anyone but me. I can see how hard he is for me, so what better gift than taking his virginity? I'm going to be the best big stepsister ever. I'll even dress up for the occasion. I know what would turn him on. The best part is that he'll get to do whatever he wants to me. I'm not saying no to anything. I'm all his, and he can cum wherever he wants on his special day.