Cat Vibrating Tail. They can also exhibit this behavior during playtime. The shaking/ vibrating can affect either the entire tail or just its tip.

Pull the tail of the mouse and it shakes, shutters and vibrates enticing your cat to play. They can raise it up and down, sweep it fr. It can also be worth trying to create more spots for your cat to hide or buy a platform for your cat to sit higher so they can.