Glottal compression is one of the best ways to keep from losing your voice.
Glottal compression is the concept of holding your breath while you sing (like holding your breath under water and talking).
The sensation is like you are holding your breath in the lung rather than in the throat. When you have maintained the open throat technique so well that you don’t have to constantly remind yourself of dropping the tongue, jaw and keeping the back of the throat open, you will find that you can learn to regulate this air both in the lung and in the neck. (not squeezing off the throat).
Finally, using this advanced breathing technique you will be able to use it for everything from air control of your head chest mix all the way to a controlled “stressing” of the chord to achieve a desired level of distortion. Without these mechanisms working in concert with each other, you will have an extraordinarily hard time distorting the voice and maintaining any kind of good vocal health.
I MUST emphasize one more thing. After distorting the voice, it is critical, the next day to ALWAYS come back and warm up the voice clean. No distortion. This will give you control and allow for elasticity and freedom back in the chord.