The problem with the glands if they are full is they give the dog that "full up" feeling, which is why they usually scoot around on their bums (we call it doing a "Brian the Snail" (Magic Roundabout??).
We took the family to Brean (near WSM) a couple of years ago, and were walking up the endless beach, when Barley decided to do a "Brian" - she scooted along for ages, and left a lovely snail-like track in the sand - we collapsed when a couple coming the opposite way said, in passing "You can get cream for that, you know" !!!!!
The glands are located at about 8.20 if you take the anus as the middle of the clock .... You have to push in at both on the outerside quite hard, and then squeeze them together (with some kitchen towel in front) and if this doesn't work, then go for it from either side with one finger inside and the other presssure outside! It's either that or pay through the nose (!!) to go and get the Vet (or a Nurse) to do it ...
I can appreciate that it's not something that anyone can do ... !!!