I'm trying to learn circular breathing to extend my range of "advanced" techniques. I had asked my teacher for advice, but he said he was a "natural" at circular breathing (meaning he has never learnt it and could circular-breathe from the get-go) and couldn't help me.
After following the famous straw-and-a-glass-of-water method for a few weeks and reading through a number of resources (for example, one at tamingthesaxophone.com and another one at woodwind.org), I have come across what I think is a major flaw in all of these explanations, and I'll try to describe it in a bit more detail.
Breathing in through the nose while pushing air out of the cheeks is all nice and dandy, and you eventually do get used to it, but a major problem arises once you start blowing air out normally and only using your cheeks for when you need to breathe in. After a while (0.75-1.5 minutes) I personally feel the need to breathe out through my nose, which I can only assume to be a reflex of some kind. It feels similar to suffocating (when you feel an urgent need to breathe in), except it's an urge to breathe out. It happens regardless of how much air is stored within the body. It only occurs when regular breathing out is added on top of pushing air out of the cheeks. If I only use my cheeks, I can go on for hours without ever feeling that need to breathe out (I'm assuming that's due to me breathing out in small increments every other time while pushing air out of the cheeks). What's up with that, and how does one actually "combat" that problem? Because each and every one of my straw-and-a-glass sessions basically ends with me spending a few seconds breathing out like a maniac.
Another problem that none of the sources seem to mention is the actual trouble of having a mouthpiece in your mouth. I personally can't puff my cheeks out with a mouthpiece plugging the oral cavity, because all the air escapes into the mouthpiece straightaway. Is there a trick to it? Does one use their tongue to "close" the tip opening, or does one use a smaller tip opening for circular breathing? A smaller chamber?
I'm asking those questions in the hope of expanding on existing resources. I feel like they don't go into enough detail and brush over some of the more important aspects of this technique.