Colonoscopies are both terrible and awesome at the same time, but you can make it go a lot smoother (pun intended) by avoiding tons of hard to digest food in the two days leading up to the prep, and being very hydrated on prep day.

Alas, I don't have a colon any more, but when I did, I wrote: https://www.jeffgeerling.com/blog/2017/colonoscopy-or-mount-...