I used to have an “outie” but the prolapse was painful at time so I saw a colorectal surgeon and he converted my loop colostomy to a “terminal” or “end-type”. So now it’s all tacked inside to keep it from prolapsing and it’s an “innie” and much less painful than it was prior. I’m happy with the choice I made. With the loop it basically just brought a small hole of the colon to the surface l, allowing secretions from below the stoma to next up into the bag but often stool would go from the upper portion to the lower portion and cause me a lot of pain and time on the toilet. My rectal area was severely burned by radiation and doesn’t stretch (hence the colostomy) so I wound up with an obstruction.
What I’m getting at is that it doesn’t matter if you’ve a sunken or prolapsed bowel but it only matters that it’s comfortable and as pain free as possible.
Be kind to your ostomy and it’ll return the favor!