Noises?

I've got my Jenks on my shoulder right now and he sounds like he's grooming but I'm not sure (he might just be eating my hair), I don't think he's bruxing (or at least not bruxing in happiness this being his first sojourn on my shoulder with a curious dog nearby.)

He's right by my ear and he's cleaning and he sounds like he's chewing a little too. What kind of noises do (possibly stressed out) rats make when cleaning?