In any of the various forms of wrestling, is it permitted (or forbidden) to tickle your opponent? It seems to me that tickling would be a great way of distracting a ticklish but stronger opponent, especially if they have you in a hold. In fact, for particularly ticklish opponents you could even win the match by forcing them into submission with a tickle.
I’ve never tried it, but I’m fairly sure that tickling wouldn’t have any effect when the adrenalin in pumping. I doubt you’d notice it.
In one of the various forms, known as professional wrestling, it would seem to be allowed, but is far less effective than hitting one’s opponent over the head with a chair. YMMV.
On second thought, change “professional wrestling” to “professional acting.”
On third thought, never mind that. The acting isn’t professional; I know some second graders who do a better job.
I’ve been in fights where clocking me straight in the face didn’t faze me because of the adrenaline. I doubt tickling would amount to more than feeling like someone was scratching an itch for me. IME, tickling isn’t just about stimulation on a tickle spot; it’s about the anticipation and the stimulation depravation of all other points. If I’ve got someone in a hold (note: I’ve never wrestled), I’d have to think that I’d be engaged in a way that wouldn’t allow me to get squirmy with anticipation.
I’m not sure that tickling requires the deprivation of stimulus at all other points. A lot of people can attest to being tickled while restrained (by malevolent siblings, mischeivous lovers, etc.).
Wrestling referee checking in. (Freestyle and Greco-Roman. Conversant in high school rules, but I don’t officiate it.)
Sure, it’s legal. It’s just not terribly effective.
If I had someone in say, an armbar and they tickled me, I’d only put more pressure on their arm as one of us is going to give up and I’m guessing me being tickled is way less effective than his arm snapping.
I can attest that in submission wrestling it’s considered very bad form, and a repeat tickler may have trouple finding training partners.
What if I say “cootchy-coo” while I do it?
you have to wait until the ref is busy restraining your manager
Hey that was once my post! 
So nothing like this would ever happen then? What a pity! (skip to 3:06)