actually the 15 second thing isn't exactly accurate, after a few seconds most of the good shit in the hit is already used up, so pretty much you're breathing back in all the tar and nasty stuff of the hit, at the sake of at most 5% more thc.

not a very healthy choice, especially since you have chronic smoker lungs. blowing up the balloon i can understand why it would make you not want to cough as much (becuase it's exercising the lungs), but in all seriousness you've basicly used up all the actual goodies.