The Right Stuff

The "fingers turning yellow" thing is actually a fairly significant chemical burn. You're rubbing your fingers in white phosphorous, which ignites at 10 or 15 degrees above room temperature (thus the "smoke", which is actually phosphorous pentoxide), is highly toxic (as little as 15mg can kill you in 7 to 10 days), and causes severe necrotic burns with a yellow, waxy appearence and a garlicy smell. It'll absorb into your skin when you get burned. If you ingest any quantity of it, you will likely die.

Don't breathe in the smoke, either; it probably won't kill you, but it reacts exothermically with water, meaning that it's a severe mucous membrane irritant. Holding a wet cloth to your mouth while you are near the smoke will counteract this.