ChrisEdwards:As you descend, just as you will feel the pressure on your ears, your mask will also start to push on your face.
Does this happen to you regularly?
Normaly the mask will equalize via the nasal passage. I have had it happen if I begin to congest a bit mid dive in cold water.
Nevertheless the more they know before the trip the better. You never know what will be left out of the briefing.
Pete