Well, I had a breakthrough!
I just surprised myself. I believe I just successfully Vasalva Techniqued my left ear for the first time ever in my life. The doc told me I just may never have actually DONE it before, and he may have been correct. He said that every time I got a chance or thought about it, I needed to try to Vasalva.
I wasn't blowing hard at all, but I had my head at a very unusual angle -- like as if I'd been hung on a noose, to use a rather horrifying image. When I finally got into just the right position and Vasalva'd, I could hear a "sticky" bubbling, crackling sound that reminded me of sucking the last bit of soft drink out of a cup through a straw, and for a second -- total clarity. My ear actually pressurized! Now if I can just repeat this exactly underwater and do it enough, I'll have it down perfect!
My ear feels a little weird now, like I haven't completely released all the new pressure out of it -- it doesn't hurt, though, and there's no vertigo or hearing loss, so I don't think I blew anything. Also, it's going away the more I swallow and chew.
A question, though: what do you guys think I was hearing when I heard that crackling sound I mentioned? Was that the mucus blowing out? Earwax being displaced? Membrane forceably opening for the first time in forever? Should I maybe try to do one of the wax flush treatments they have?
Now to repeat this triumph and I can succeed! And my instructor's going to let me try in the pool session on Monday! Very excited with my progress, as you can see!