Sometimes dogs get a condition called dead tail or cold tail. Their tail becomes limp and no longer carry it up as they usually do. This can and someimes cause pain and discomfort. It is brought on by vigorous exercise, cold weather, taking a bath outside in the cold.
This usually will go away after a couple of weeks. If you believe it starts to cause him pain you can give him Baby Aspirin, 1 tablet per 15 pounds of weight 2 times per day.
Also some dogs when they have upset stomach and start to feel nauseous or diarrhea coming on will not want to move too much and will hold their tell limply down.
Please let me know if I can be of further help.
Peace,
Christina
.

If I was helpful, please press the
green ACCEPT button to show your approval. Thank you!
Peace and happiness to you and your pet! ~ Christina
.