One of the best movie scenes I've ever seen showing what it's like to get hit hard enough to TKO is in the movie Snatch. Brad Pitt's Pikey boxer takes a shot and to give the audience a good impression of what he is feeling, instead of hitting the mat, he is plunged into dark water and is struggling trying to figure out which way is up. That scene left me just shaking my head as the best metaphor I've seen for it.
You feel like you are moving slower than you are trying to, and your brain is basically arguing with your body as there is a delay in everything. This causes overcompensation of your balance, arms and legs moving farther or shorter than you intend.
One thing that is hard to get across for me to others that it gave the impression of, I couldn't feel the floor correctly from the disconnect in the neural pathways. Or a better way to say it, you go to step and your foot stops faster than you think it should or longer than you think it should. Distance judging is out the window. When Kevin Lee did his dance, that's what happened to him, I can promise you that.
If you recover before a stoppage, you end up still off for a bit as vision and concentration is narrowed for a while and I remember feeling like my limbs were moving faster than they should have been until the cobwebs were fully cleared.