A number of methods exist which allow you to open your Eustachian tubes and equalize your ears. Some require pinching your nose, one doesn't. I've marked that one in blue.
The most common method of equalization is the Valsalva Maneuver. Named for Antonio Valsalva, this technique involves pinching off the nostrils and blowing gently into the nose. Never blow forcefully while attempting this method as a too forceful Valsalva Maneuver can result in the rupture of the eardrum, round window or oval window. This will usually result in immediate vertigo and hearing loss, which can be permanent.
The Frenzel Maneuver was named for developer, Herman Frenzel of the Luftwaffe in World War II. This method is preformed by closing off the vocal cords, pinching the nostrils and an effort is made to make a "guh" sound.
The Toynbee Maneuver is simply pinching of the nostrils while swallowing.
Beance Tubaire Voluntaire (BTV) or Voluntary Tubal Opening is the preferred method of equalization once mastered. It feels very much like a yawn and a difference in tonal quality of sounds will be noticed when successful. The muscles of the upper throat are used to pull open the Eustachian tube.
You should employ equalization techniques immediately upon descent and continue them regularly on descent. If any pain is experienced, you should ascend until all pain disappears and begin again.
Often divers find it useful to chew gum or eat foods such as apples or carrots prior to diving. You should not attempt to chew gum or eat while diving. Another equalization technique divers find helpful is to gently massage the area under the ear, just behind the jaw. This gentle massage is most effective when used in conjunction with one of the other equalization techniques mentioned above.
If you are unable to equalize ear pressure, it is possible to rupture the eardrum, round window or oval window. This will usually result in immediate vertigo and hearing loss, which can be permanent. If you are unable to equalize, you should abort the dive.
