Frenzel is done closing the nostrils!
The most used hands-free method is BTV, which does not require to do ANYTHING, just open the tubes, using the proper muscle, which is there for this purpose.
Problem is that less than 1 over 5 divers can control that muscle...
I learned it at 6 years, when swimming in the pool.
Usually people who have control of the specific muscle also have good control of other things: they can wingle the ears, curve the tongue at U, etc.
Often people learn to control the muscle while performing other actions in the same area, such as closing (raising) the soft palate, yawning or swallowing.
But it must be clarified that pure BTV does not require swallowing, yawning or doing any of these "auxiliary" actions, a pure BTV is motionless, except for the contraption of the muscle which opens the tube.
And the airways remain open, you can breath while opening your tubes.
See here about BTV:
The hands-free equalization technique, also known as BTV (béance tubaire volontaire) or VTO (voluntary tubal opening) in English, is a very useful but optional technique one can add to their
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