Duck, various folks here have written about using a catheter to empty their pouches. There’s plenty of variation, but some of them have described using a bulb syringe (essentially a turkey baster) to irrigate the pouch, squirting water in to facilitate emptying. Just inserting a catheter will only work if the pouch contents are fairly liquid. If stuff has been stuck in your pouch for a while then it’s unlikely to still be liquid. Do they even know if there is stool in your pouch?
The key diagnostic question is where things are getting hung up. I still suspect the malpositioned pouch.