Definitions for "Squirm"
To twist about briskly with contortions like an eel or a worm; to wriggle; to writhe.
to move in a twisting or contorted motion, (especially when struggling); "The prisoner writhed in discomfort"; "The child tried to wriggle free from his aunt's embrace"
Keywords:  wiggling, act
the act of wiggling
Strut instability caused by internal pressure on the bellows.
Failure caused by excessive internal pressure that causes the corrugations to break out and shoot into an "S" OR "U" shape.