Verb. The act of inhaling vapours or otherwise chasing the dragon on a piece of tin foil. Illicit narcotics, usually opiates are placed upon a piece of flat tin foil, and then heated on the underside of the foil. When smoke begins to appear, the foil is tilted, so the narcotic will slide. Not only does this produce a large amount of smoke, it will leave a black line on the foil, essentially "tracing" a path of waste.
Yo nate has been tracing all day, not cool, he does this every day.