Article: What you’re doing is establishing a second source of air that you can use when your lungs run out. While this may make you look like a chipmunk, the more useful analogy is to think of yourself as a human bagpipe, and your cheeks as the bellows. Close your jaw, but make a tiny opening in your mouth, and use your cheek muscles to push the air out slowly. Continue to breathe in deeply through your nose. Control the motion so that it takes between three and five seconds to blow out the air in your mouth  Experts differ somewhat on this step. Some recommend keeping your cheeks puffed out the entire time, refilling them frequently with little bits of air from the lungs. Others, however, suggest that it might be more natural to let your cheeks return to a normal breathing position as you let the air out of your mouth.  Experiment with both to determine which is more comfortable—and effective—for you and your instrument. Since you have been breathing in through your nose the whole time, your lungs should fill up by the time the air in your mouth runs out. You can change where the air is coming from by closing your soft palate. You should do this right before your lungs run out, so you have time to fill your lungs again while you are using the air stored in your mouth. Once you are able to turn it into a seamless process, you will never have to pause to take a breath while playing your instrument again.

What is a summary?
Fill your cheeks with air, and breathe in and out through your nose. Blow out the air you have been holding in your mouth. Switch to exhaling using your lungs when the air in your mouth runs out. Fill your cheeks with air again. Repeat this sequence continuously.