No sedation for me, either. It seems unnecessary. For me, the procedure isn't horrible, but the FEAR of pain tends to be more of an issue than the actual brief discomfort of a flex sig.
As to the idea that there is no reason not to have it if offered, I disagree. I recently was given an IV medication following minor surgery (unrelated to j-pouch stuff) and went into acute renal failure from it and spent weeks in the hospital on dialysis. I've never had any kidney issues before, never had any reactions to medication before and I'm not allergic to anything either. Now, almost three months later, my kidney function thankfully has returned to normal but my eyes were opened to the risks that you never think will happen. Not worth it for a flex sig, for me at least, since it wasn't that bad.
I'd suggest bringing an iPod and ear buds, listen to some relaxing or meditative music and it will be over before you know it. Good luck.