Why don’t UFC fighters tickle their opponents?

Like, pin them down and really torture tickle them. Surely you can’t train being ticklish out of someone. Hell, even just tickling someone’s ribs or armpits while in a clinch would be enough to throw em off.

Maybe giggle really loud as you tickle them too, to throw them off their game. Yeah you can train for trash talk, but if a grown man starts to giggle and tickle you in the middle of a fight it’s gonna throw you off.

So why don’t they tickle their opponents?