What is Smooth One's / Sb's Feathers?
1.
to make oneself (or somebody else) feel less irritated or offended
Lacon was no fool, and the Cousin's wrath just when everyone was trying to smooth their feathers was a thing to be avoided at any cost.
John le Carré: The Honourable SchoolboyRONET BOOKS, Hodder & Stoughton, 2000. p. 63.
