Yawning...

[franulele]

From what I undersand yawning after or durring singing is a sign that you are signing correctly as your embouchure is "dropping" so to speak (losening up). Embouchure is essentially your mouth and jaw. If you are constantly yawning though.... Thats a lack of breath. But yeah several reasons your body yawns

UH is right. Barring obvious reasons like lack of sleep, the occasional urge to yawn while singing means that you are raising the soft palate & keeping an open throat while singing. That's a good thing.Remember the feeling in the back of your throat & try singing some open vowel sounds in that position. You'll probably get a big sound.

 

[lizaloo]

This is a complete stab in the dark as I have no professional experience with this, but proper (at least classical) singing, especially around high notes, involves opening your mouth and lifting your soft pallet to the extent that you're nearly yawning. And yawning once often makes you yawn again, right?

Perhaps you just have overly-good technique.

 

[camface]

I yawned when I read this topic. I guess it IS 3:30 in the morning.