There appears to be some sort of nerve complex where they are pressing. I severely damage my inner ear on the right side years ago scuba diving. Mostly deaf on that side.
If I press in just the right spot as these folks were doing, I get a "bubbling" sound in my "ear". Obviously no sound at all, just stimulating some nerve to send an auditory signal?
That’s interesting.
I had trigeminal neuralgia for a few years - horrible problem nicknamed ‘suicide disease’ because folks have killed themselves over the pain; at the time they didn’t know much about it but may know more now (mine wasn’t the typical problem, but caused by a cracked tooth that they took forever to discover). There’s a nerve involved that starts somewhere in back of the head and goes out to each side of your face. I wonder if that has anything to do with this ‘thumping’ technique...
Sounds like you never drained your ear of sea water............Just kidding!