Little white on baby tongue

My little one has a little bit of white on his tongue. It's not a lot & surely doesn't look like thrush. He's not bothered, still nurses like a champ. It's just in the middle theirs a little streak. Not on the tip of the tongue , more so in the back. You know how sometimes we stick our tongue out & their is a little white in the middle/back ? That's what it looks like. I called his pediatrician to ask, but does anybody else experience this ? First time mommy here !