First off, it's a fetish. By definition it means sexual attraction/fascination by something that is generally considered non-sexual by culture. Shoes, underarms, sneezing, there are so many things that one can look at and not understand how it could be sexy in any way.
And a lot of times if you don't have the fetish it just won't make sense. I still can't understand how a sneeze fetish works or how someone can be turned on by artwork and stories depicting forced sneezing.
So in that regard… if you don't get, you don't get it. Oh well. Nothing can really change that.
But to TRY and explain aspects of it that can be hot, or how it can be introduced into other activities, well I'm sure some of us can do that.
Sure, maybe simply tying someone up and tickling their stomach doesn't appeal to you, but how about holding someone close and running your fingers lightly over their skin so that they writhe and giggle against your body?
What about tickling someone's foot and telling them if they pull away you'll spank them?
Or ramping up a bondage scene by initiating that instinctual panic and urge to struggle with some tickling when they can't see or fight back?
Or humiliating someone who tries to act all strong and tough by reducing them into a squealing little ball just by using your fingers?
Or coaxing someone close to orgasm, then tickling them until they come down a bit, and repeating until they're begging to cum?
Fun fact: Did you know some hardcore BDSM people who do things like trampling, CBT, needles, longterm isolation, have tickling has a 'Hard No' for them? Not because it's too vanilla or light, but because they can't stand it for more than a few seconds?
To us, there is something hot about the loss of control, the rush of endorphins and dopamine, the power (or lack thereof) that it can bring. There's an appeal to the sound of laughter and begging and the sight of a body writhing in restraints. Some will insist there's even an intimacy to it by having the constant skin-on-skin contact.
And to anyone who says it has nothing to do with BDSM, I'd certainly like to see them take just 20-30 minutes of tickling without shouting "Yellow" or "Red" at any point.