From nowhere, you produce billows of smoke out of your mouth...it's like you've manufactured smoke in your lungs!
Secret: Not gonna lie: this will probably kill you. You probably shouldn't do it. If you are insane enough to try this, here's how it works: Strike a match, let it burn, and then shake it out. Notice how when you strike a match, there's an initial sulfur flash (during which there's very little smoke), followed by a simple burn (during which there's practically NO smoke)... and finally, when the match goes out, you see lots of smoke? Good. That's what your audience will see.
What they WON'T see, is that when you first strike the match, that initial sulfur flash has some kind of vapor (read: potential poison), that, when inhaled, will (I kid you not) ...become smoke in your freaking lungs. Read that last sentence again: If you inhale that sulfur -whatever-it-is at the exact moment you strike the match, it will become smoke in your lungs.
Right now, you should be asking two things:
#1: How does it work?
And #2: Why isn't everyone doing this trick?
The answer to #1 is: "I don't freaking know." It's wizardry as far as I'm concerned. All I know is that when you inhale that crazy sulfur-poison (at least I assume it's poison. I don't really know. In fact, let me reiterate that nobody should do this trick, ever), the invisible gasses somehow become smoke inside your lungs. From the different responses I've gotten in humid versus dry climates, I've actually begun to suspect that it has something to do with the water vapor in your lungs... like when your breath looks like smoke on a cold, dewey morning.
The answer to #2 is: because it burns like a Muthaf#$%a. The first time you try this trick, your eyes will water, your nose will sting, and you'll want to freak out... be cool. Just act like nothing's wrong and exhale slowly... Voila! Smoke from nowhere. Once you've practiced this for a few weeks, you'll have it down. Remember: strike the match towards your face, and whatever you do, don't react to the burn. Just play it cool, relax... and exhale. Ta da!!!