If your holster does not hold the gun securely, get rid of it and get one that does.
Guns falling out of insecure holsters in public restrooms:
Note that all of these are just the ones where the gun fired and made the local paper. I have literally dozens more in my files, all equally tragicomic. I have even more stories that I've heard personally from talking to people who dropped a gun that did not fire and that did not make the news.
Guns left behind by people who took their guns out of the holster:
Bottom line: if you have an IWB or OWB holster that does not hold the gun securely, it’s time to upgrade to one that does.
Who wants to be the next headline? Not I!
Oh, as an aside? If you ever do
drop a gun, let it fall. Never reach for a falling gun! That's because modern, quality firearms cannot fire when they strike the ground, despite what the headlines above might imply. All except one of the above shots were almost certainly caused by someone reflexively reaching for the gun as it fell, and unintentionally grabbing the trigger. Let it fall!