Its a pretty effective method, but its still nowhere near perfect, since it does leave a faint smell of smoke still, since when you light the bowl/bong there is always excess smoke burned off the top, expecially because a lot of people are under the impression that the goal is cherrying the entire bowl.

The only perfect method is smoking in the shower. Steam up the shower, blow the smoke in there and even hop in to get rid of any possible trace of smoke smell. Flawless method.