The Only Use

writhe
in
Fahrenheit 451
(Auto-generated)

And then he was a shrieking blaze, a jumping, sprawling gibbering manikin, no longer human or known, all writhing flame on the lawn as Montag shot one continuous pulse of liquid fire on him, There was a hiss like a great mouthful of spittle banging a red-hot stove, a bubbling and frothing as if salt had been poured over a monstrous black snail to cause a terrible liquefaction and a boiling over of yellow foam.†
p. 113.5

writhing = moving in a twisting or contorted motion

Definitions:

(1) (writhe)
to move in a twisting or contorted motion -- often of a person when struggling or in pain
(2) (meaning too rare to warrant focus)