I've had 2 colostomies in the last 8 years. The reason I had to have the second was simply because they found/removed polyps on the first one.
The first one was pure hell simply because they gave me a sedative, so I was semi-conscious through the procedure and it felt like they were trying to take me tonsils out from the other end. After the procedure the Dr told me I was all over the table and hard to hold down and I told him "You should have been on my end Doc!"
When I had the second one they had an anesthesiologist present because they had to put me out. Much better. All I remember is waking up afterwards and the nurses trying to get me to sit up and get my act together.
As far as the prep beforehand, that crap they made me drink was done right nasty! The nurse told me that the best thing to do is have an ice cold glass of water handy. Drink the fluid and then GULP the water as fast as you can to try and "lessen" the taste. If you try to mix it with other liquids you like, hoping it will somehow lessen the taste, it ain't gonna work... PERIOD!
And after you drink it, prepare to do a Jeff Daniels (Dumb and Dumber)
YouTube - dumb & dumber-A very funny scene