Do you know that there are three technical compensation that divers can use? The Valsalva maneuver, is the method of diving taught normally for equalizing the pressure in the middle ear. Toynebe maneuver: swallow hard keeping the mouth and nose closed pushes air into the eustachian tubes and relieves pressure on the middle ear.
Frenzel maneuver: Move front muscles of the mouth from one side to another to open the eustachian tubes. Valsalva maneuver: On the nose, breathing lightly and directing the air exhaled into the nose, but blocking it so not out of the nostrils. Thus air will be directed by the eustachian tubes to ear medium.