Illinois Prison slang for something generally unimportant yet still held dear.
Example:
You're in the chow hall and you have a couple of salt packets. Someone takes one without asking. You look at them incredulously and say "What the fuck are you doing, Joe?".
"Getting some salt." comes the reply
"I know you didn't do it without asking 'cause I'd have to fuck you up the ass and make you like it." you threaten.
"Damn, Joe, it's just a pack of salt." he says.
"Listen muthafucka, I don't care if it's a doodoo with cheese. It's my doodoo with cheese, and you ain't touchin it without asking. Got it!?"