I was very resistant to wiping my own ass until I got a friend.  One day we were in the bathroom together (we used to cross streams all the time -- don't judge me) and he suddenly plops on the toilet and noisily shits, wipes himself and pulls up his pants.  I never called for mom to wipe my ass after that, although there were some shitty drawers involved for a time as I mastered the technique.  