I've had two of them. First one, I was wide awake. I asked the doc to show me the tool after he was through. Bad idea. Very long and the idea of it was frightening. Best way to experience it is to be asleep. They put you down with the minimum drug needed, and you wake up with a little gas.
And whoever said the prep was the worse part of it is correct. Just to clean out your bowels. First time, I had to drink a gallon of the most awful stuff. Sit close to the toilet for your own safety and that of your family. Nowadays, you don't have to drink a gallon, but it's very potent.
BTW: The last time, the doc said I had some polyps and wanted to do it again in two years. Coming up on 3 now, and I guess this September, I get violated (inspected). Probably better than dying, though....
What would be the best line for this experience. "Did you find Osama Bin Laden while you were in there?" or "WMD"? I think I saw an internet joke with a bunch of punch lines for this...