Passing gas in a stealth manor, usually while walking through a crowd or a group, so that someone else gets blamed for the stench, or at the very least people besides the assailent must suffer it.
The restaurant's so busy tonight that you can get away with crop dusting your own section
When crop dusting does NOT work:
1. on a treadmill (no matter how fast you walk or run)
2. with a strong tail wind
3. with a turnaround - for example, you crop dust while walking with your girlfriend, then she turns around and walks back to look at a display in a storefront window.