“I’m going to bore a hole and I don’t know where,” I sing as I raise my hand, index finger pointed squarely at the writhing body of my four-year-old, and wind the finger clockwise in an even-tempered circle. She squeals, curls into the fetal position, turns, stretches, screams, and essentially revels in the tension I’m deliberately building as I continue, “so I guess I’ll bore it…right…” my hand dives a few inches toward her belly, and as her hands dive likewise to protect the helpless soft skin there, I dart toward her forgotten clavicle. “In…” I hum, and her hands dash then instinctively to protect her neck. “THERE,” I cry, the tickling equivalent of a banzai charge, as I deliver the final blow-a solid armpit carpet bomb, digging my index finger deep into the well of her axillary lymph node-toward which I’ve been building this entire time. The song helps me carefully construct the anticipatory foundation of well-blended terror and mirth upon which all successful tickling campaigns rest. But it’s that strike that she’s been dreading, yet longing for, since the moment my hand went up. She erupts into the most uncontrollable cackle, the best kind of laughter, the kind from deep down behind the belly button and somewhere inside the most ancient part of the human gut. She’s hating every minute of it, on one level. Her wriggling, squirming body is contorting itself in an effort to break free and, yet, the moment she can muster breath enough, the only thing she’ll shout before her plea of “again” is that I “stop, stop stop!”

And even when I tire of this game, I can’t, in fact, “stop, stop, stop,” until she tires of it as well. Which I guarantee you will be long after I have. Because here’s the conundrum of tickling: she can’t tickle herself.

We can’t tickle ourselves.

I can sit around with my index finger up to the third knuckle in my own armpit all day long and…nothing.

It takes two to tango. And to tickle.

Why?

Entire articles have been written about what happens neurologically when we get tickled. But it all boils down to this: our brains interpret tickling as a potential attack and the laughter and flailing is the outward manifestation of internal panic. The parts of our bodies that are most ticklish are also most vulnerable. When we laugh and beg for mercy, we’re displaying an evolutionary submission response to our aggressor. And when a mother tickles a child, when the child begs for more and when the mother stops when she’s told, a bond is strengthened.

But that panic, though.

The laughter is born of pain.

And the fact is that all comedy, all humor, has a foundation of tragedy, is related to what saddens us.

Negativity and positivity are inextricably linked. One’s sense of humor is the only thing that makes one woman’s pessimism another’s sarcastic wit.