A note about anal glands: they truly *should* empty on their own and should NOT need regular
forced emptying by a groomer or anyone else. Anal glands that do fill up a little should naturally empty by being "pushed against" by a dog's firm poo. If this is not happening - and/or if the anal glands are becoming WAY too full - you need to switch to a higher quality food with less fillers (fillers can cause voluminous, mushy poos) so the poos can firm up. Really, the only time a dog should need regular anal gland emptying is if there is something structurally wrong in that area.
Folks should tell your groomers *not* to empty your dog's glands because once they start this process, it can interfere with what your dog's body is already taking care of on its own.