Just curious. I have YET to find an easy way!

I have a baby bathtub, but I always get water in DS eyes and he hates it. I can't wash his hair in the bath tub because of this.
I bought a sponge shaped like a bear and I put him in the big bathtub and lay him down on that...this works but I am afraid of getting water in his ears and them getting infections. I don't out hardly any water in there, just enough to keep him warm...
any suggestions to make this time easier?