This technique is an ancient Eastern meditation as well as a great way to fall asleep.
Lie on your back with your hands behind your head, fingers interlocked, and your palms cupping the back of your head. Get as
relaxed as possible (This position may take a little while to get used to).
Place your thumbs in your ears so that you are pressing the outer flap of your ear and blocking the entrance to the ear
canal.
Lie quietly and listen for a high-pitched sound that you will gradually hear inside your head.
Lie there for 10 to 15 minutes and concentrate on that sound. Then put your arms to your sides and go to sleep.
(Don’t worry about all the stories of people who have ringing in their ears. This is different — and natural.)