A raise in your pay that equates to change that can be found in ones couch. Often this change comes from your own pockets or guests who sit down on your couch.
"Hey, I heard you got a 3% raise, congrats!"
"Fuck that, it's a couch raise."
"Couch raise?"
"It's $5 more on every paycheque, I can find more than that between the cushions of my fucking couch every two weeks"