"It's a slang term for the claustrophobic reaction that can occur when people are shut in together over long periods of time. The feeling of claustrophobia is externalized as dislike for the people you happen to be shut in with. In extreme cases it can result in hallucinations and violence—murder […]." (1.64)
Come out! Come out, you little shit. Take your medicine!" (4.45).
Beside his Daddy, in the other front seat, was a short-handled mallet, its head clotted with blood and hair. (4.66)