i saw the blue angels in Omnimax. Itr was interesting watching them, since, at the time, I had no clue why the hell they were grunting and making the faces as they turned.
I'm fairly certain I know the technique you are supposed to use to avoid passing out. Basically, you have to tense up your entire lower body and neck in order to keep your blood from just simply being forced out of your head.
I used to do it for fun, where I would basically tense up my neck and sorta push. my entire face would turn bright red, veins stand out all over my arms and neck, and if I hold it for long enough, I drop, not fully unconscious, but total tunnel vision. Since it's all done with muscles, there's no danger, because as soon as you start to pass out, muscles relax and blood flows again. Only danger is if you hit your head on the way down.
I would kinda like to try something like that, just to see if I could take it without passing out.