not all sex is planned...you can't rub one out if you get some ass that is unexpected. a friend of mine told me that the best way to hold on for longer is to stop or slow down, and do what you do when you are holding a piss. while you do this, just make sure you breath. that should help a little, although it takes some practicing and you have to make sure the girl you are with stops too. also try thinking of something that might take your mind off of it...like baseball or something...