Cat Tail Language: Common Positions & What They Mean When a cat fails a jump, slips, or gets startled and then immediately swats after someone laughs, the reaction is usually tied to sudden overstimulation or redirected frustration rather than The Definitive Guide to Cat Behavior and Body Language Tuft & Paw Why Do Cats Puff up Their Tails? Plant City Animal Hospital Why does my cat wiggle the top of his bum with his tail straight up in the air?