Have a towel with you that you are sitting on. I found that out when running to the toilet during the drinking phase. My couch wasn't close enough to the bathroom!!
You can put some jello (NOT RED) into the drink to give it some taste. Read the directions. Do it all just like the directions say. If you don't, the doctor may not be able to finish the test. First of all, he or she needs to be able to see in there. Second, if it's not cleared out, he could hurt you and not mean to. I'd hate to be told that I had to pay for the second test because I fudged taking the medicine...
You go in, change clothes and they give you an IV in your hand or arm. Then they put you on the table and give you the meds to put you out. You wake up 20 minutes later and you don't know you had the procedure. You get dressed and someone takes you home. Your husband or helper gives you soup and puts you straight to bed.
You aren't supposed to make any decisions that day or sign any legal papers because the medicine makes it so that you don't quite think straight.
The only real pain you should experience is the bloated feeling in your belly. You get rid of that by walking around your house the next day - not exercise, per say, but regular getting around. You have a lot of "air" in there that has to work it's way out.
The good thing is that you will know before you leave the hospital what the doctor found. And he will remove anything that could potentially be a problem.
Just to let you know, I was on a plane 2 days later for vacation.
Good luck!