A dog's tail can be described by the following adjectives:

1. Short: Dogs' tails are usually relatively short, not as long as those of other animals.

2. Curl: Many dogs' tails are curly and shaped like scrolls, which is the characteristic of dogs.

3. Be good at wagging your tail: A dog's tail is a way to express feelings. When they are happy, excited or friendly, they wag their tails.

4. Furry: A dog's tail is usually covered with fur to make it look furry.

5. Flexibility: Dogs' tails can swing, flip and bend freely, which shows their flexibility.