I fuck my best friend's brother and I can't believe the cock he has!

I visit my friend after a long time without seeing each other and I see her stepbrother very changed, he is big and muscular, nothing like I remember him, I can't help but look at him with desire, he notices it and we start flirting and when we see each other alone we can't stop and we end up fucking in the living room without letting his stepsister see us.