(It was only the amusing John gritting his teeth, I am able to explain).
"The feeling is coming back, my boy," said the Phoenix, gritting its beak.
"I'm afraid it has," replied his comrade, gritting his teeth with displeasure.
Colon turned on the prisoner with a black face, and gritting teeth.
Gritting his teeth on the bit of his pipe, Russ cursed soundlessly.