Ear Rumblers Assemble!
A couple of days ago someone asked this question on Reddit:
What's a sensation that you're unsure if other people experience?
I answered with this:
I can compress some muscle inside my head, just in front of my ears, and it makes a rumbling sound. I always wondered if anyone else does this.
And that's when I discovered that, after more than forty years of wondering, I am not alone. In fact, there was already a subreddit dedicated to this ability, called r/earrumblersassemble. It turns out that this ability is available to individuals who can voluntarily contract the tensor tympani muscle of the middle ear. It's a phenomenon which has been known about since (at least) 1884.
The Ear Rumblers Assemble subreddit is now a hive of activity thanks to all the new members and is full of people asking questions like "Does anyone else use their rumble while beatboxing?" (yes) or "How long can you rumble for?" (about 30 seconds). One redditor even suggested that, now there were so many of us, we should try a global, synchronised rumble to see what happens (I predict catastrophic earthquake).
Does it have any practical uses? I sometimes use mine to help concentrate, or drown out noises I don't want to hear. I've read that SCUBA divers do it in place of the Valsalva manoeuvre. Beyond that, I don't think so. I like to think that maybe we'll be invaded by some kind of sound-based alien race and the only people who will be able to repel their sonic mind-control are the ear rumblers.
I look forward to joining the resistance soon!