Communication between a cat and a person can occur in different ways.
For example, a pet may snort, purr, meow, rub against your legs, bite, release its claws, and demonstrate other signals.
The cat's tail is not the least important of these communication channels.
For example, if the tail is raised and its tip is curled, this means that the animal is relaxed and feels safe.
You can tell that your cat wants to greet you, is happy and excited, by its tail being raised and straightened to its full length. If the cat comes up to you, wraps its tail around your leg and starts rubbing against you, it means it doesn't mind playing.
But if the tail is raised and straightened, but trembles, and the pet simultaneously straightens its hind legs, this means that it is marking its territory.
A neutered cat shows his anxiety with this position.
If a cat sits and moves its tail from side to side, it means that it is exploring the territory. This is what a pet does when it wants to check whether it is safe around it, or if there is danger lurking nearby.
By the way, such movements are typical for bored and irritated cats.
But vigorous tail wagging indicates that your pet is nervous or anxious. He may even be preparing for a fight. Often, this behavior is accompanied by loud purring.