Having had three colonoscopies so far, my system for prep is to change what I eat at least the week before. Jello, ice pops. . . generally light stuff. At some point before I start drinking the beverage from hell, I get butt cream. Smear it on and then drink. Keeping a layer of diaper rash ointment on the tush helps a LOT.

I suggested to the pharmacists at my local pharmacy they should recommend butt cream when someone buys the prep stuff. Not sure if they do it, but all agreed it was a good idea.