This phrase is one of a kind. It has utmost emphasis and is a prime example of when someone does not care. The phrase is not to be used in a public environment unless you truly "Don't give a fuck". This slang sentence is used primarily when under criticism, because when you don't care what somebody else says, whip out an "I don't give a fuck!" and they'll shut their fucking mouths ;)
When you fail at something in life (eg. failing an exam or not getting a job), go home and spend an hour just standing in the shower, propping yourself up against the wall with your eyes on your feet.
Caleb knew the only thing to do after he didnt get prefect was take a failure shower.