... and when flying! (normally, I mean)

Just thinking about it now ... I kinda pull my jaw back a bit and push my tongue against the back of my throat, like the first half second of a swallowing action. It's enough to make a little 'click' in my hearing, even when I've not changed altitude.

I can pop my ears by plugging my nose and making a "k" or "g" sound. Comes in handy since my Eustachian tubes are essentially useless.