Ah, yes. That glorious sense of accomplishment. SWEET VICTORY! If I remember correctly I was given a popple as a reward. (In fact, I'm almost positive it was a "Baby Cribsy Popple" as seen in the "Items Guide" section.)
I definitely remember watching toilet training videos, but not QUITE like these (via The Crotch Blog, which sounds bad, but is really just...bizarre ;D) Definitely check them out!!