Believe it or not, this topic has actually come up before... WAY before... I'm thinking May of 2008...
I think my response was something to the effect of "set it on top of the TP dispenser if it's level enough." Now that I'm older and wiser *ahem* that's probably not the best answer in the world. When I have mine on, it stays in the holster, and I will the pants to stay at my knees and not hit the floor.
<insert Yoda voice here> hmm the force is strong in this one hmm yes....