This isn't about a medical condition, but a strange phenomena that has puzzled me for ages. I am able to flex _something_ that gives me the sensation of surprise, similar to a the sensation one feels when a rollercoaster rockets up a hill and is just about to go back down. I can't pinpoint the exact location besides it originating somewhere in the back of the neck or head.

As for how I learned this, it's an odd story. When I was a child, I would hold my breath and "push" to make my face bright red in a matter of seconds because I thought it was humorous at the time. Of course, this can't be a good thing to do, but from it I learned to flex this whatever it is independently of making my face red.

As a final note, flexing this... Thing during meditation seems to deepen the state and intensify the artificial sensations felt in one's forehead and fingertips. I view meditation purely as a psychological thing, with experiences caused by lack of sensory input among other things. Knowing more about what I am flexing would allow me to search more about what it is in the internet, and deepen my scientific understanding of meditation.