I did mine 7 years ago when I had diverticulitis. My colon had already fistulaed into my bladder (hole between the two) about a finger-width in diameter, so I was farting and pooping where I shouldn't have been.
Yes, the go-lyte solution tasted like burnt plastic dog crap, and yes, I drank the ENTIRE gallon that night before. No, I didn't sleep, as I couldn't rest long enough between screaming shits to actually, you know, get off the can.
So the tranqilizer didn't work 100 percent, because I felt them shoving a telephone pole with a camera attached up my ass. Then I got the, "you'll feel a little puff of air" line. Little puff? You bastards just set off a fire extinguisher in my ass, or hooked me up to a 185 compressor!
Finally the deal is over, I get home, and guess when that air all decided to come out? Yep--right on my couch. THREE MINUTE NON-STOP FART. Not farts, or string of--ONE SINGLE EXTENDED FART.
Even the dog was scared.
But, 36 stiches and minus 10 inches of colon later, I'm all better. Whee.