If there is too much accumulation fluid, they can swell and become engorged. When this happens, if a Poodle eliminates and the bowel movement is hard or large, it can press against the sac(s) and cause one or both of them to break open.
Alternatively, when engorged this can cause discomfort and itching. A Poodle may then scoot his/her rear on the floor or ground in an attempt to relieve that feeling. It is not uncommon for an owner to mistakenly believe that the dog is 'wiping' him or herself after going to the bathroom.
But this is actually the actions of a dog that is in discomfort from swollen anal glands. When a dog does this, the action may cause the sac(s) to break open. If all of the built-up fluid is expelled in this way, the smell is quite terrible. Some refer to this as a skunk odor or an exceedingly strong musky smell.