I must had been eight or nine, maybe younger. I’d gotten a blood blister on my heel. It fascinated me seeing it. The little purple, hard bubble of blood, those things are. I let it be for maybe a week before I started poking at it. It began with just stabbing it with a pen. Eventually once it was torn, I scooped the remains at once with a nail clipper. When I did that, I was overcome by the sensation. It did not hurt me, as all the skin of the bottom of the foot, particularly the heel, is callused. So I went in for more. I clipped away at the skin of my heel with the nail clipper, taking off little bites of flesh with each clip. This became a habit, lasting perhaps a month, until someone noticed my foot was chewed. I stopped doing it, but once all the skin was healed over, I did it once more. It was just the sensation of clipping that I enjoyed. Were this painful I can’t see myself doing it. Someone noticed, again, gave me a talk and I retired the habit.