Does this look familiar:
While a mildly amusing commercial, it is most likely a sign that Toby has an anal gland problem. I certainly hope that "Mom" checked out poor Toby before calling about steaming her precious carpet.
If your dog is scooting, obsessively licking or bothering its back region, you need to go and check things out to make sure everything is working as it should. If there is a discharge, bad smell, or swelling, its time for a trip to the vet.
So, what on earth are anal sacs and what the heck do they do? That question is best addressed on the marvistavet site, which includes interactive "where are they" and "how do you squeeze them" Web interface. It may become all the rage in interactive game playing.
If that's not enough the kind folks at Expert Village have provided a video on how to "express" anal glands:
While I wish they would have picked a lighter colored pup to do the demonstration to make the particulars easier to see, you probably get the point.
Please note: if you do express your pup's anal glands, you may want to invest in some cheap rubber gloves (exam room gloves in a box are available at most pharmacy stores), and if you have a weak stomach, you may just want to take your pup to the vet and have it done, its a most foul smell.
Here is another that discuss some of the common issues with anal sacs.
From personal experience, if you pup has constant anal gland/sac issues, you may want to talk to your vet about diet. If there isn't enough fiber in their food to give them firm stools, or if they have a condition where their stools are consistency soft, then that could contribute to the issue. Stools need to be firm in order to give that natural squeezing of the anal sacs during a bowel movement.
A dog with hip, back or hind leg issues may also suffer from anal sac issues, as they may be unable to "assume the proper poop position" to sufficiently empty out the sacs when they have a bowel movement.
Also, from personal experience, the TYPE of food may be causing issues. I have one such pup who gets anal gland issues whenever he eats a fish-based diet. Change his food over to a chicken or beef-based diet and the issue clears up.