Please don't romanticize invasive diagnostics. If you want to advocate for the occasional bowel purge or using anesthetics to sleep have at it though. But also, general anesthesia should be avoided as much as possible, it's not a trivial matter.
The movicol prep stuff they give you isn't ideal either; you've got to drink a lot of odd tasting fluids that then give you basically explosive diorama which can be awful in itself. It also causes some people to explosively vomit as well (it's designed to make your body want to eject it asap) which really isn't fun when it's trying to escape both ends at once.
The actual procedure isn't amazing either. A camera down either end is uncomfortable at best ranging to extremely painful (short term) as they try and get round the corners in your bowel. There's also the potential it to go wrong in some nasty ways or for odd side effects, and at absolute best, you're still stuck on a table trying to make polite conversation with 2m of camera tube stuck up your bum.
Can confirm your refusal to confirm; none of it's a thrilling or trivial experience.
I wasn't knocked out but I might as well have been as I didn't feel any pain and kept kind of drifting off half to sleep. It was completely fine and I'd not worry at all about getting it done again.