The solution to this problem is anal gland cleaning. The following are the specific steps:
1. Put the dog in a quiet and comfortable environment and ask someone to help fix the dog to prevent it from moving.
2. Wear disposable gloves and clean the dog's anus with warm water and special detergent for pets to ensure cleanliness and hygiene.
3. Gently press both sides of anus with a paper towel or wet towel to find the position of anal gland. The anal gland is located at 4 o'clock and 8 o'clock in the anus, and it feels like two pea-sized sacs.
4. Dip a small amount of warm water in a paper towel or cotton ball and gently press the anal gland to empty it. Be careful not to use too much force to avoid hurting the dog.
5. After cleaning, clean the anus with warm water again to ensure cleanliness.
If you are not sure how to clean the anal gland, it is recommended to consult a veterinarian or a professional pet groomer for help. They will provide you with more detailed guidance and operational skills.