We've done it a few times. You can see all the movies on my OF page (136 videos there). I jerk off when he gives me his load, because that's when I usually get the most cum from him and it's sexy when he's a little dominant!
Does he prefer to jerk off into your mouth? Just wondering. I would like to see you suck his cock while he cums in your mouth at the same time. You know just keep sucking as he is still cumming. That would be hot