Choo Choo's don't take baths

Right now Tanner doesn't want to wash his hair. Only his hair. He has no problem taking baths, he actually enjoys them. Especially when I put bubbles in there for him. He will wash his feet, legs, arms, face, ears, everything except his hair. We have told him recently that bugs will build houses in his hair and if we don't wash them out they'll just keep on building. That works. I have to look through his hair to find out how many bugs have moved in(there was 5 this morning) and then he'll finally let me wash his hair. Today just wasn't working even just to get him in the bath. I had put bubbles in his bath, he had his favorite toys, I had even told him he could choose his clothes for the day, all by himself. No way, wasn't going to happen. Then I hear him coming

"Chugga chugga choo choo, chugga chugga choo choo. Momma me a choo choo".
"You sure are, you're a nice train. Now come on lets take your bath".
"Chugga chugga choo choo. Momma, me a choo choo".
"I know honey, come on".
"But momma, choo choo's don't take baths".

Cherstin