The tapping back of skull has been reported a few times here and other places. I suspect it is a very common fix (even if temporary) for people on hackernews:

The tapping back of skull has been reported a few times here and other places. I suspect it is a very common fix (even if temporary) for people on hackernews: - https://trudenta.com/this-simple-trick-may-help-with-tinnitus/ https://trudenta.com/this-simple-trick-may-help-with-tinnitu... First time I did it, it was profound. I hadn't realized how much I missed complete silence.