Let's Laxvox - by Brigitta Gumbricht

Insert the end of the tube with the markings into the water up to or below the first marking. Hold the tube at this height with one hand. The tube must not touch the bottom!
Place the other end in your mouth between your front teeth and on the relaxed tip of your tongue, gently extending the tongue slightly.
Gently enclose the tube end with your lips. Keep your cheeks loose and relaxed. Do not bite on the tube!
Hold the bottle/glass close to your body at chest height.
Exhale actively first, then let the air flow in passively, keep your abdomen loose, and start bubbling directly. Shoulders and chest remain down, only abdominal movement.
Relax after each bubble (make a silly face, relax your jaw muscles, and let the air flow in passively).
Bubble the sound, as before, with a straw into the water.
Start at a medium pitch and go deeper.
The higher the pitch, the more intense the training, later go to the vocal limits without straining.

Speak short and long soft "oohs" (as in "moo") into the tube. Let your cheeks vibrate.
Say a long "oooo" and vary the pitch. Keep your jaw loose and relaxed. Move your lips forward (pout) and sound long and loud enough.

LAXVOXING FEELS EASY AND RELAXED. YOU DON'T NEED TO MAKE AN EFFORT.

Make glissandi up and down in the tube.
Sing simple melodies into the tube (e.g., "Happy Birthday", "Brother John"). Test what changes when you push the tube deeper into the water.

Slowly remove the tube from the water while singing. Keep all other settings.
Practice with the tube in the water and then slowly remove it from your mouth. Otherwise, do not change anything!
Then practice without the tube saying "oohs" and humming "mmmm".

Count from 1-10 with the tube and then without the tube, say the days of the week with the tube and then without the tube, speak short sentences with the tube and then without the tube. Read a text aloud with the tube and then without the tube.