A place in which one can store many useful items such as: a shiv, drugs, a file, keys, a gold watch (like Butch's father). The term seems comes from trying to smuggle contraband into prison.
"Quick Bob, the cop is walking up to the window. Hide the shit."
"I don't have anywhere to hide it!"
"Use your prison backpack."
"I don't have anywhere to hide it!"
"Use your prison backpack."
by walker_flocker February 13, 2016