Re: Shoulder Holster
If they're what I picture them being, you draw the pistol out from the side of your torso, either with the barrel pointed down or towards the back. Not sure how they'd be the same as something strapped to your tricep. Though given, I've never seen a pistol strapped to someone's arm at all, so maybe I'm missing the appropriate tropes. Wik 18:05, 2 November 2011 (UTC)
Re: What is a frog
Moving the answer to this question over here.
A frog is a canvas or leather flap that allows for multiple sheaths or scabbards to be fastened to one hip. Not sure when use began, but they were certainly used during the 18th century. (I've owned one for re-enactments). A soldier could carry a bayonet, a throwing axe, and a saber on the same hip, though it could also be used for several knives or whatever.