Term used to describe when a diesel engine is blowing a thick cloud of black smoke. Also common with yuppie teenager's who have there parents pay for a nice diesel truck and then put a chip in it to blow smoke.

Rolling coal is the act of modifying a diesel engine to supply a rich fuel mixture. This produces large black plumes of smoke. Sociologists have studied the connection between inbreeding and the modified diesel engines for many years.
The act of rolling coal has come to be known as a celebration in the United States as the love and commitment you share with your family.

A large diesel truck equipped to blow large clouds of black smoke to signal a desire for deep anal fisting

Laying down a long fart while ascending an escalator. Preferably done after saving your farts for as long as possible to maximize emissions of fecal particles.