Farting while walking. Usually to avoid blame. Since walking creates a substantial pocket of air to in your wake, it also helps to wave your hand in front of your anus to allow the fart to escape this vortex.
While on my way to the bathroom, I was almost caught crop dusting the office. To dissipate the smell, I causally waved my hand in front of my anus to allow the fart to escape the vortex.
The act of releasing flatulence in a silent but prolonged manner as one cruises at a constant velocity so as not to draw attention to oneself. The key factor in what makes a crop dust a crop dust is the victims heads, and therefore olfactory receptors, are at or below the anis of the perpetrator of the crop dusting, as the gas comes from above and settles on the victims like the plants of a field.
“Damn, tha was an OG Crop Dusting!”
“How so?”
“Because I felt that stank come down on me like a blanket of mustard gas came down on the soilders of WWI! It was lethal, even for a mouthful!”