Why does tjaden have a special grudge against himmelstoss?

Himmelstoss seems to pick on Tjaden. Himmelstoss tries to "educate" Tjaden using cruel practices,

Tjaden is a bedwetter. Himmelstoss tried to cure him by finding another bedwetter and meking them sleep in the same bunk. One would sleep on the top one night, the other on the next. Unfortunately, whoever slept on the bottom bunk would end up on the floor and get sick. The men got there revenge by catching him alone in the dark, stripping of his bottoms and giving him a whipping.