TG,
Yep, we're shaped differently. But my IWB Glock is subject to the same gravity that yours is.
If there is no risk of the gun
falling out of the holster, there's really no reason to
take it out of the holster -- and lots of good reasons not to.
Every time a firearm is handled with the trigger exposed, there is the potential for an embarrassingly noisy mistake. Minimize handling the firearm unnecessarily, and you minimize that risk.
Further, taking it out of the holster greatly increases the chance that you'll set it somewhere foolish (on top of the TP? hanging from the hook on the back of the door? on the back of the toilet?) with the resulting risk of dropping the firearm or leaving it behind when you finish.
Setting the firearm in your underwear is the best of a bad series of options if you start by taking the firearm out of its safe holster. But which way is the muzzle pointed while you're handling that firearm? Safe direction...? I don't think so! Keeping the gun in the holster, with its trigger covered, is still far safer and far more secure.
Given an otherwise secure setup and if the only trouble is that it's flipping over, put a hand on it to stabilize it while dropping your drawers and doing your business. Or put a hand on it to stabilize it while dropping drawers, then rebuckle your belt below the knee while doing business.
Just don't take it out of the holster, with the potential for leaving it behind, dropping it, fumbling it, or inadvertently doing something stupidly dangerous with it. Leave it in the holster where it belongs.
That's all I'm sayin'.
pax