Squeeze your nose and blow!
Please do not listen to these idiots.i used to live on the lake and i can honestly tell you the Best and Safest way is to use one cap full of regular rubbing alcohol in each ear.it will work and kill any bacteria.id you foot beleive of call your local ER. also please do not bang yourself in the head.
A bunch of things to try:
Put your head below your heart. Like stand up and bend over. Seems to help me, anyway.
Someone you trust should gently suck out the ear canal.
I think there's an App for that.
shake it. sideways. works for me after a dive
Wash it out with some water.