I get an occasional build up in one ear. Had the nurse/assistant do it one time - never again, I do it myself.
When they did it, the spray blast was sometimes hitting my eardrum directly (which she couldn't really tell), and was like jet engine loud, though not really too painful.
I've done the lay on the side with warm oil, then water/peroxide mix, then flush, but that's kind of awkward. I found that a bulb syringe with plain warm water, shot it at just the right angle to flush things out seemed to work as well and much easier, and no chance of irritation from the hydrogen peroxide.
-ERD50