Use when hiding strong personal opinions or emotions, often to maintain harmony. During the meeting, I bit my lip rather than argue.
Pro Tip 2/3
Tactful Silence
It suggests diplomacy; choosing not to speak may be more influential or appropriate. I had to bite my lip when he boasted about his questionable achievements.
Pro Tip 3/3
Conflict Avoidance
Implies avoiding confrontation or keeping the peace in a challenging situation. She bit her lip when her mother-in-law made a snide comment.