Watch Your Mouth

The boys and I were playing in the shower tonight when I made the statement, "Alright, it's time to wash your hair."
Caleb said something smart about not wanting his hair washed to which I gave the fatherly response, "Watch your mouth."
His eyes got big. Fear came over his face. "No, Daddy, don't wash my mouth."
"What?"
"Don't wash my mouth," he said, lip quivering a bit.
"I said watch your mouth like with your eyes."
Even more fear. "No, Daddy, don't wash my eyes."
Sigh...light bulb..."Okay, I won't. Can I wash your hair?"
With a head nod and a look as if he'd just won a battle, "Yes."