With technology keeping much of our attention sometimes you have to take it back to basics. There's very few guys that will pass on some ass to play Call of Duty though.
If blocking the tv with your ass bent over doesn't work, you can give him some head while he's playing the game. He'll either stop playing because he's too distracted or let you finish while he finishes.
If all else fails pull it out and sit on it while he's playing the game. He'll stop.