To bite your lip is to hold back what you were about to say. Bite your lip and let it pass.
The physical act stops the words, which is why it works as a picture. To bite your lip is nearly always the right decision and nearly always resented at the time.
1phrasebite your lipTo hold back what you were about to say.
“You will have to bite your lip through the whole of the speech.”
bite your lip is a gesture.
Practised in Body Language & Gestures