Quivering, Wagging, Puffed Up: What is Your Cat's Tail Trying to Tell You? Anyone else's cat do this? She vibrates her tail when she is happy to see me It looks like they are vibrating. When a cat's tail shoots straight up and quivers or rattles at the tip, it is the highest form of excitement they can show. It's a Why Do Cats Shake or Vibrate Their Tails? Vet Verified Reasons Explained Catster A Guide to What Your Cat is Communicating: A cat's tail is far more than just a balance toolit is a sophisticated emotional barometer that broadcasts their internal world. When your feline she always vibrates her tail at this exact spot very.. confused?? anyone else experienced this? : r cats