If the scent sacks get too full on each side of the anus it is very uncomfortable for a dog. It rubs its butt on the ground or bite round it. Some vets put a finger inside the anus to express the fluid. OUCH Comic had a bit of blood showing once
I researched and do it myself if need be.
I would just gently pinch the area and the sacks empty. I would do this in the bath tub because it squirts out. The scent is like rotten mushrooms and looks kind of like diarrhea. It is instant relief for the dog. I have not need to or attempted to do this on Mya.