gack back - The agony in your back after you've been bent over like a f*

The agony in your back after you've been bent over like a f***ing pretzel on a bender of blow and meth.

My back is so gackin' back I think it's gonna start doing push-ups.

I bent over so much my back is now a f***ing hinge.

I did blow and meth so much my back is now a f***ing meth lab.