Toothpaste for picky child?

🦋 • мσммιαηα x 3

My son is 6 and he doesn’t like any of the toothpastes I buy. He gives me such a hard time. I found a strawberry flavor and he liked it for a week and then doesn’t like it anymore. He wants to just brush his teeth with plain water. We’ve tried regular minty, plain, strawberry. I’ve even tried to brush his teeth w/toothpaste myself and that didn’t work. Any suggestions?