Skittish horses have inspired many an equine expression. Consider "He won't stand hitched" or "She's chewing her bit." Other apt examples: "She's so nervous she has to thread her sewing machine while it's running" and "He's as nervous as a long-tailed cat in a roomful of rockers." But one saying in this category reigns as the undisputed classic: "Nervous as a whore in church."

Jumpy as spit on a hot skillet.

Calm as a june bug.

He makes a pressure cooker look calm.

Hotter than a burning stump.

He'd worry the warts off a frog.