I'm not ticklish. Never was, not even as a kid. My son, though, is a different story. He is ticklish in the normal places: the tummy, under the arms, by the chin, the soles of the feet. That would be enough for most children, but he’s an overachiever, and is ticklish on a broader, more ambitious scale. The backs of his knees are ticklish. His back is ticklish. His chest is ticklish. His butt cheeks are ticklish, which really seems like a serious strategic error on his part. His ears and scalp are not ticklish as far as I can tell, but that doesn't help him much.
Obviously, if your butt is ticklish and your back is ticklish and every other part of you is ticklish (with the possible exception of the ears) it’s hard to defend yourself. My son takes a Korean martial art, Tang Soo Do, which is supposed to help with this sort of thing, but either there’s no tickling in Korea or else he has not internalized the proper defense, because his martial arts skills don't seem to help. If there is some way to block access to front, back, sides, bottom, and everywhere else simultaneously, he has not learned it yet.
He also hasn’t learned self-control and/or stoicism in the face of distress. That famous Bruce Lee clip where Lee’s been cut and he licks the blood off himself to prove that he’s just that tough, impassive and impervious to cuts with sharp blades and/or tickled? That's not my son. When he's tickled he completely loses his shit, at least semi-literally (there is often farting). He thrashes like a bass on a hook that’s charged with high voltage. He spasms; he throws himself about; he disturbs the cat. He shouts, "Oh, God, why? Help me! Stop!" My wife is convinced that the neighbors are going to call Chicago family services on me. The cat wishes they would.
If you were ticklish from the bottom of your feet to your butt and beyond, you’d probably treat potential ticklers with a certain respectful distance. You’d exercise, I'm certain, a wary caution. My son, though, deliberately provokes me. He attempts to tickle me, though he knows I am not ticklish, courting massive retaliation. "Do you want to be tickled?" I ask him. "Do you want to disturb the cat?" He says he just wants to tickle me like I tickle him; it's all about retribution, apparently. But since I'm not ticklish, his plans for revenge are all doomed. There’s no justice in the world, and existence is filled with woe and lamentation and some people who are more ticklish than others. I feel this is an important lesson for him to learn.
I've been tickling him going on 10 years or so now, not constantly, but with intermittent steadiness. This week he's going into fifth grade. He's not as tall as me, and probably never will be (short genes from his mom) but he's built sturdily; as he gets bigger, his thrashing has started to imperil not just the cat, but the structural integrity of the house. Not too long from now, puberty will come along and he’ll probably get less ticklish, as well as less defenseless. Even if he still wanted me to tickle him, which he will not, I won't be able to. You only get to torture your child for so long. I try to enjoy it while I can.
—Follow Noah Berlatsky on Twitter: @hoodedu