Refers directly to Till Lindemann, lead singer for the German Industrial band Rammstein. It refers to the fact that he has put on a little...erm...Weight and it isn't muscle. Also refers indirectly to someone who has put on a few pounds.
He looked a bitlike the Tillsbury Doughboy in their video for "Mein Teil" didn't he?
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 failureshower.