De civilitate morum puerilium libellus

What becomes the lips.

To press the lower lip with the upper teeth is unrefined, for this is the gesture of one threatening, just as it is to bite the upper lip with the lower. Furthermore, to repeatedly lick the edges of the lips with a circling tongue is inept. That the lips were previously a bit too extended, as if composed for a kiss, the paintings of the Germans indicate was a sign of endearment: to mock someone with an extended tongue is buffoonery.
Spitting.

Spit while turned away, so that you do not spit upon or sprinkle anyone. If anything rather purulent has been cast onto the ground, let it be trampled underfoot, as I said, so that it does not cause nausea to anyone: if that is not possible, catch the spittle with a small cloth. To resorb saliva is unrefined, just as that which we see some people do, not out of necessity but out of habit, spitting at every third word.
Coughing.

Some people cough indecorously, repeatedly while speaking, and that not from necessity but by custom: this gesture belongs to liars and those who are thinking up what they should say while they are speaking. Others are even less decorous...
Belching.