Here ya go, best I could come up with. It's a belt that, when combined with a few more bucks at the hardware store, means you can keep that bag up and to your side tightly, while still guarding your stoma.
Use this belt: https://www.stealthbelt.com/stealth-belt-pro
Along with cutting a 2-1/2" or 3" PVC pipe (or any plastic) in half. Then, glue either weather stripping or firmer foam along the new edge. I used these foam barriers that would normally go between an electrical outlet/switch and the wall to prevent water from getting in the crack. Take a look at the pictures I uploaded along with the belt.
Simply put the guard/shield, what have you, over the bag whilst wearing the belt a tad looser than you would without the guard in it. You can even leave the belt unzipped throughout the day so it drains away and drains quicker, then when you want to be more active, simply rotate the guard to let your bag rest to the side and zip up the bottom. This will allow you to put some significant force directly onto your stomach and again, hold the bag to the side. 