It's interesting that you say that Bob because I had always wanted to play one for many years but believed that I did not have the lungs for the job, having seen some of those big built Aboriginis, however, large lungs are not required as you do not 'blow' into a Didge, you merely vibrate your lips and store your air in your cheeks refilling them as needed, sort of like storing air in the bag pipes. This is known as 'circular breathing' so the sound doesn't stop even when you take a breath. Some ladies can do this when they are talking. .
Alan.