My girlfriend says she knows when I'm ready for bed or going to work based on if she can hear me trying not to throw up in the bathroom while brushing my teeth.
My gag reflex starts at my teeth. To answer for real though, I can't brush my tongue. Things touching my tongue, aside from food, makes me gag very hard. I'd never make it in Miami.
It's not even the toothpaste, but the brush itself that bothers me. Same thing happens when I get throat swabs by the doctor, throw up a decent amount of the time from it. Pretty much anything touching my tongue or throat makes me puke.