This exercise is level 4 in the Face the Squat exercise developed by a group of Chinese Kung Fu masters in the mid-1900s. There is one more higher level that I know of.
If you want to learn, please start at level 0 to avoid injury: - Stand with your toes, knees and nose against a fence. Feet togerther/Knees together/Face the wall. Relex for a few minutes. Hold the fence with your hands. Slowly go down and INHALE when you feel the need to inhale. When you cannot go down anymore, wait until you feel like to exhale then slowly stand up with your exhale. Each set is 50 repetitions. Work you way to be able to do a full set and then do a few sets a day. Go slowly. Usually takes a few months to get to level 4, but took me 2 years practicing about one set once a month.
If level 0 is too difficult, you can cheat a bit by separating you feet or move a slight bit away from the wall. Please let me know if you are intersted to know more about the Chinese Face The Wall Squat Exercise so that I don't waste my time explaining.
Thanks you. Please be careful. WARMING: Never do this without a wall because if your knees extend past your toes this exercise can cause knee pain and injury.