Short hand for the phrase "niggas are going to make excuses" usally used when someone talks trash claiming they are going to win a game of some sort then lose and blame it on a number of things before the game is even over.
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.