Hi Tricia - my stoma is an oval, also, and I use the Hollister plates that have a very thin plastic tear-off backing. I have been using an old backing as a template as long as I can, but they are flimsy and don’t last long.

Are you also using the barrier rings? 

I change every three days; at that point the barrier ring has deteriorated to the point where I begin to worry about my skin. All in all I am ok with this.

And I know just what you mean about the vacuum effect! Mine does that sometimes for no reason at all that I can figure out - how in the world does this happen? When I see it I open at the top or bottom to get a little air in (I use a two-piece drainable set). And it is a mystery!

@llholiday ...  I used to use the barrier rings from the start of my ostomy.  Then after reading here, I decided one day to try it without & I found I had wear times of 5 to 6 days.  It was awesome for me.  I've never used them since.  I have a dip beside my belly button, about 4 inches long,  which was never put back in place after my last surgery, which is under the wafer so I just spend extra time pressing on that area to try & get good/ better adhesion of the wafer to my skin.  Heating the wafer with the blow dryer works very well for me. 

Oh, the vacuume affect is what I call....   "reverse farting!" Lolol... 

@dlkfiretruck  I too have a dip now on the underside of my stoma . This is something new for me after my surgery as well as a kind of new buldge that kind of acts like a visor or an awning and I literally have to lift up that awning bulge to put my new appliance on. Also after getting it on , I'm noticing the ring melting around and even onto the stoma. If I put the hole in the bag up to my stoma there is too much room of skin exposed I'm.wondering if my stoma has shrunk again  since my last stoma nurse appt. I'm wanting to try without a ring but I see all that exposed skin around it. 

For now I set up an appt with the stoma nurse to address some things there bags just are not holding up as usual.