Английский словарь американских идиом - watch one's dust

or watch one's smoke {v. phr.}, {slang} To notice your quick action; watch you do something quickly. * /Offer Bill a dollar to shovel your sidewalk, and watch his smoke!/ * /"We'll have your yard cleaned in a jiffy," the Boy Scouts told Mr. Truitt. "Watch our smoke!"/ * /"I can go to the store and be back in five minutes," bragged Tom. "Just watch my dust."/