Kenny,
You will not wake up wanting to go the bathroom, although you may need to pass gas when you wake up as during any pouchoscopy, the pouch is inflated with air. So you will have the desire to fart, and will fart. You haven't indicated where the stricture is, but if he is dilating it during the pouchoscopy, a MUCH bigger concern is the risk of perforation of your bowel when they stretch out the stricture. I had 3 dilations of a stricture in my Pouch inlet and was warned with each procedure of the risk of perforation and emergency surgery if that happens. They usually use a balloon to dilate but he may be using the scope itself. Depending on the stricture size and location. If you do perforate it will likely be spotted during the procedure and acted upon quickly. They may get informed consent from you to deal with that issue if it arises. I was told in rarer cases the perforation manifests after discharge and the patient develops extreme abdominal pain. Your doctor should have discussed with you how he or she is intending to dilate. Mine was done a little at a time, gently, first to 11 mm and then 15 mm and then 18 mm. The last of these dilations was in January and had held up through my scope on June 6, 2022.
Good luck Kenny and let us know how it goes.