My stepbrother (you) was supposed to cover for me while I went to a concert but when I get home, you've changed your mind and you want something in return if you're going to keep my secret... at first you just want a blow job, but as things progress, you keep asking for more and more, especially as I get more and more bratty about it. Eventually you make me put in a butt plug and you fuck me until I'm practically speechless, but i regain my composure and tell you I'll tell our parents about this little blackmail situation you've put me in if you don't keep quiet about that concert!