… they WORK. Have fun with a new cartoon!
If you witness your dog scooting on her butt across the floor or desperately trying to reach for her back, all that accompanied by a fishy smell, you may likely be dealing with some anal gland (= anal sac) issues.
Or maybe you just notice that fishy smelling “souvenir” on the couch after your dog has left her favorite hangout spot. That may be a sign that the glands eventually emptied on their own, after they probably did not during your dog’s last #2 potty business.