Disclaimer: I'm not an endocrinologist, so I might have no idea what I'm talking about.
For about a decade, since my early teens, I've had an ability to induce a set of sensations within myself at will. First I feel like there is something in the back of my head that tenses just a little bit, then I feel a tickling sort of sensation throughout the backs of my legs. From the back part of the upper thighs down to the ankles. Sometimes I can't quite control the intensity. I get carried away and the tingling gets to be too much and I spasm for a second to let out the steam. I can repeatedly activate and disable this mechanism several times a second. My best guess so far is that I can somehow release small amounts of adrenaline into my system at will.
Does anybody else experience this? Any explanations?