to polish the crap until salable. Usually applies to making something appear more desirable than it really is when in reality it is a steaming pile of fecal mass. Can be used in any situation involving making things that suck look less suckier and passing them off as being the coolest fucking thing on earth.
"Time for a new update, lets just apply some turdshine to the old release and charge them for the higher version number."
"Congressman 1: How can we pass this bill that fucks over Americans?"
"Congressman 2: Lets rename the previously failed bill and try to pass it again!"
"Congressman 3: We owe our paychecks to turdshine."
When you go to the bathroom to throw up and there is a Turd already in the toilet (left by you or someone else) and you still throw up on it. So the vomit is sitting on the Turd like people on a ferry ride.
Bro I just threw up and added a few more passengers to the Turdski ferry!