Now and again, I manage this vocal trick, but not consistently. Sometimes it is there, sometimes not, and I haven't been able to figure out what I am doing when it is there, so I can repeat it on command.
But now, having taken a singing for the vocally-challenged class, I have access to a voice teacher.
So I went to take a lesson ...
Nobody ever asked her to teach them that, she said. Let's give it a try.
We booked half an hour. She listened to me sing a song. Thought about it for a few seconds, then said "Try it like you are pissed off."
So I did, and there it was. Took all of five minutes.
Boy, is she good.
I have to practice, of course, but it was as easy as that. Intent.
Why didn't I know that?
Live and learn ...