It's extremely important to equalize your ears early and often during descent in order to prevent a squeeze. Equalization is accomplished by adding air to the middle ear through the Eustachian tube.

Divers use several methods to equalize their ears. The most common is the Valsalva maneuver, which is performed by pinching the nose, closing your mouth, and gently exhaling until you hear or feel the pressure in your ears equalize. When using this procedure, take care not to exhale with too much force, as damage to your ears could result.

Some divers are successful at using other methods. These include wiggling your jaw, yawning, swallowing, or tilting your head from side to side. These methods can also be used in combination with the Valsalva maneuver to make equalization easier.