After taking a poop, you do a poor job of wiping your ass leaving "rust".
"Dude, I totally did a rust job after I took that crap and now my ass is incredibly itchy."
by Johnny B123 January 01, 2008
When you or you partner shit's all over their hands. Then using the shit or crap as lubricant. Then you may apply this lubricant around you or your partners privates.
Damn she gave me a nasty rust job last night.
by rusty man September 29, 2011