Each site requires finding the right pouch and the additions to make it seal. When it burns, it's not sealed. I've tried so many products and the Marlen deep convex is the only pouch that works for me. Your situation will be changing as your pregnancy continues, but if you don't get a seal, you need to look into a different pouch or a different application. Once you find one, work with it. I requested samples from every company I could find.
Is your actual stoma site recessed into your abdomen? This could help. I could never get a seal until an ostomy nurse fit me with Marlen deep convex pouches. With a Marlen deep convex one piece bag and multiple additions toward skin side, I get a solid seal. The additions layered before attaching to skin are Hollister 4"x4" cut to fit size of stoma and rounded to fit inside the wafer. Attach to the 4x4 around the stoma opening a Convatec stomahesive strip which has been folded in half. This may be enough for your pouch to seal.* If so, you may add paste, or not. Note: if your abdomen creases when you bend, you need to add a filler to fit into the fold, for example, add extra paste or ¼ of a moldable ring molded to fit each fold. Then attach the prepared 4x4 with Stomahesive strip, etc. to your ostomy site. Add the pouch to the applied 4x4. *I have to also add an eakin cohesive stomawrap over top of the Convatec stomahesive strip.
What is the stoma size? And do you need convex pouches. I do have a lot of pouches that worked before I had a parastomal hernia repair. And, a bunch that were ordered after the surgery that didn't work for me.
Keep trying, but don't keep doing the same thing and expecting to get a seal. I know it's miserable, but that means you haven't found the pouch and additions that work for you.