The reasons why dogs always lick their butts:

1. Some dogs whose intestines are infected with parasites will feel itchy and lick their buttocks.

2. Dogs have an anal gland on each side of the anus. When the anal glands are swollen or infected, the dog will lick the area near the butt to relieve the discomfort of swollen anal glands.

3. If your dog often plays in the grass, and then keeps licking its butt and the base of its tail, it is very likely that it has fleas.

4. If there are redness, swelling, scabs, and dandruff near the dog’s tail or butt, it means it is caused by a skin disease, and you should go to the hospital for treatment in time.

5. Generally speaking, there will be secretions in the dog’s butt. Because the dog's body constitution and diet are different, the secretions discharged are also different. If it becomes a paste, it will block the anus, and the dog will lick it when it feels uncomfortable.

6. Dogs generally take care of their hair by licking, as long as they don't lick their tail or butt frequently.