When someone uses their dirty and scabbed hands to perform secual gratification in return for goods or services. No lubricant is used and typically the scabs from the 'Duster' will fall onto the genitalia of the person they are dusting
Dude, Lauren is outside of Pilot giving a Crusty Finger Duster for a pack of cigs and enough gas to get home.
When a woman shits on a mans pecker, and dries it out with a hairdryer until completely crusted over then jerks him off until every last dingleberry is gone.
We had McDonald’s then I got a fatcrusty rusty from Becky last night.