I feel the same, I like a total clean-out, and without having to spend 4+ hours to do it in. I do know that the other suggestion of drinking what is basically a very strong laxative is something I don't agree with. First, when you drink something, it will pass through your stomach, your small intestine, then your large intestine. Second, you will need a prescription for that 'golitely' (? on the spelling), and third, best stay very close to a bathroom for a very long time!
I've had to use the golitely as a prep for a test the day before, and I spent the entire night, actually sleeping on the toilet. Nasty stuff!
And I viewed my last colonosocopy on the television while it was being done, and I don't it done that good of a job cleaning out. Appeared to be, possibly bile, but definitely some green slimy substance left over in the large intestine.
Doesn't seem to bother the doctors much, as with their scopes, they can squirt water over an area if they can't see it clearly.
If you read the bottle of the over-the-counter counter stuff, you will read that it typically states that it will take 6 to 8 hours to work. I guess take it before bed, and hope you wake up in time to make it to the toilet!
But you're not the only one to experience this, (if that makes you feel any better), I've experienced the same exact thing. After several hours, it kind-of tends to make you want to just give up, but yet not quite ready to leave the bathroom either.
You just know that there is still some water up inside you, and don't know when it's going to want to come out.