"Bad idea anyway. Your gums would probably dry out. And you'd get cheek-aches, and the last thing you want to do is wander around asking for a cheek massage."

Cheeky!

She nods. "Exactly. So they came up with 'glinting,' which is an emotion hand-signal language. And even there, I know the five-finger one-thumb two-symmetrical-arms version; there's subdialects for people with no thumbs, or asymmetrical limb arrangements."