Some time ago I read Doug's post about effectiveness of hyperventilation and decided to give it a try. The method I tried first was the following:

1. Exhale as much air as possible (using methods described by Doug)
2. Inhale as much oxygen as possible.

This proved to be more effective than the usual 'ordinary' breathing, however it still required quite a few exchange cycles before getting into the hyperventilation state. Because of that I've modified the method a bit:

1. Exhale as much air as possible.
2. Inhale as much oxygen as possible AND push the oxygen release button on the demand valve. Do it as long as you can - your lungs will expand, then your cheeks at which point you're at your maximum capacity.
3. Contract your abdomen trying to push as much oxygen as possible to your head. Make sure you don't fall down (because of the hyperventilation and the resulting dizziness). I also try to keep my eyes open as otherwise my eyeballs tend to roll up which puts some unnecessary strain on them.
4. Keep the oxygen in your lungs for a few seconds.

Using this method I found that I could hyperventilate immediately and with every oxygen exchange, which significantly reduces the time needed to abort. This method however can be a bit unpleasant (painful) because of the amount of pressure the oxygen is exerting on the lungs. I'd say it's worth it given the results.
I was wondering if anybody else used the demand valve like that and if there were any known medical considerations/long term consequences of it (after all, the pressure comes from the valve, not from the natural breathing).

When the KIP is high I breathe so desperately and rapidly I don't need the button; but when it's moderate and taking awhile to abort, I breathe in and use the button to top off the lungs. But like Joe, I'm careful not to overpressurize my lungs. God bless! lance

I'm no expert on this subject, so price my opinion as you see fit! I pressurize the lungs until they feel over full, but not uncomfortably so. I've never felt them "hurt" so I don't know if that's possible. It's also possible there is no way to hurt your lungs even if you tried! I just don't know. I think if you limit the pressure of the mask against your face, you'll be okay. It's how I've done it for many years.

Joe