Fulfilling my stepbrother's fantasy

My stepbrother is a complete shut-in and I'm getting worried. He just stays inside and plays video games all day. I know that if he were properly motivated there would be no problem getting him outside. Probably doesn't know what he is missing. I'm having sex every night and the poor guy hasn't even had a mouth on his cock. With Mom and Dad out of the house, now is my chance. I'll dress down and see if he is interested. I've caught him trying to jerk off on me in the shower before. I bet he will jump at the chance to have a piece of me. What are loving stepsisters for?