"Self-inflation of the ears to treat eustachian tube dysfunction
You may be able to improve your symptoms pinching your nose closed and “popping” your ear. This helps by forcibly air through the eustachian tube into the middle ear. You can also achieve the same effect by blowing up balloons. The pressure required to expand a balloon is usually enough to push air up the eustachian tube.
This is a very useful maneuver and may be repeated as often as necessary, whenever a sense of pressure or fullness in the ear develops. Do not perform this when you have a cold or any nasal discharge because it may drive infected mucous into the middle ear and cause an ear infection."