If you are relatively sure it's not an intestinal parasite (if the dog hasn't had fleas for the last several months ) chances are this is either anal glands or a bout of constipation (which could be mild resulting in hard, thick or pasty stools that are difficult to pass)
There's usually a foul smell, frequent licking and scooting along the floor or other signs of discomfort and excess attention to the anal area is quite often a symptom of Anal Sac Infection or Impaction.
In most cases a veterinarian can express the glands and provide quick relief for your pet while teaching you how to do this rather unpleasant, but sometimes necessary procedure. An antibiotic may be recommended as well. If this is done, make sure you finish the course exactly as directed. Stopping early will only end up costing more when you have to start all over again.
When a dog has an anal sac impaction, the glands are usually pretty easily emptied manually. Owners really should be shown how to do this by their vet or someone who is very experienced so the dog isn't hurt or annoyed enough to resist having this done.
Anal sac infection is a bit more complicated and definitely should involve a professional because there's a need to treat the infection before it spreads and becomes a very major problem.
Sometimes it's necessary to actually have the sacs removed surgically. This is called anal sacculectomy.
There's more info and photos about what might be happening here: www.dr-dan.com/analsac.htm and even more here http://lowchensaustralia.com/health/analsac.htm
This should resolve pretty soon either way - once your companion is seen.
If you'd like instructions and more discussion about this, check here:
http://www.marvistavet.com/html/body_anal_sacs.html
Addition of fiber to the dog's regular diet will address any possible constipation as well as help with the anal glands.
Good sources of high fiber tolerated by your friend would be a tablespoon or so of canned pumpkin (100% natural pumpkin, not the pumpkin pie mix); or sprinkle a couple spoons of wheat bran (or brewer's yeast), offer them a couple dried plums (aka: prunes), dried figs or even a bit of unsweetened dried coconut.
Call your vet for advice about how much Metamucil you can offer, based on your dog's health history, size/weight. Usually a teaspoon for a medium sized dog every 8 to 12 hours.
Good luck and I really hope this works out for you and yours,
Own Animal Care & Rescue
Animal Rescue&Care Org Owner; Animal Care author; Animal Behavior Consults.;Cert. Avian Specialist;