Fantastic file from W.O. Hermiston, as always. I think that hits just the right spot.
I have used a similar concept but not as directly about weaking or stretching involuntarily, mostly just about training you to keep those muscles relaxed. Check them out if you like:
Diaper Training 2: Uncontrollable Wetting:
https://warpmymind.com/index.php?gadget ... e_id=14017 (just relaxing the pelvic floor muscles)
Subliminal Bedwetter:
https://warpmymind.com/index.php?gadget ... e_id=14451 (just relaxing the muscles around your urinary tract)
and especially Incontinent Pants Pooper:
https://warpmymind.com/index.php?gadget ... e_id=14452 (relaxing the muscles and weakening/holding open sphincter)