I had the tremendous pleasure of working Wolf ( DL4NCO ) on 20M this month who intrigued me by sending that he was using an “Air Key” and that details could be found on his QRZ page ( see here ).
“The air key, a monitoring pressure switch which is used e.g. at gas burners. The air flow from the mouth is interrupted or released with the tongue to generate cw sigs.”
This definitely demonstrates “CW Character” and hats off to Wolf for this method of keying 🙂