Getting locked in some kind of fetish garment, or more general, just not being able to take something off. That could be done with actual locks, or glueing something closed, or just actually getting sealed in something, that when dried / finished processed, has no opening. The tag Chastity is always combined with this of course.
Lets Start Properly by Sumomo EX
This is one entry in an entire series by sumomo-ex involving all kinds of unbirth, vore and sex-toys. Lets Start Properly by Sumomo EX ExHentai