My mother taught me something similar as a child. She called it “jellyfish” and the challenge was to be completely relaxed in every muscle. Later I added a simple mental exercise (visualizing each letter of the alphabet sequentially). As an adult I sleep on demand; anywhere, anytime. I know it isn’t this “easy” for everyone (not really easy, it took a lot of practice).

So, I work until 10 or so and just head to bed. I’m almost always out in less than 10 minutes.

That's a real human super-power. Congrats!