As someone who as carried on and off for over 25 years, as a holder of a Special Police Commission, CCW, Forensic Investigator w/ the Medical Examiner, in a major Southeastern city, depending on when/where, etc I lived and under which circumstances, I have carried two and sometimes three handguns.
Normally I carry on right hip, just behind the quarter-line belt loop, this is very rarely bypassed, because under stress we’ll all do what we train for and will reach for the same spot each time. When I deem it necessary to carry a second gun, it is generally carried in middle-of-the-back holster. Being right handed, and consider this a back-up or surprise, I like to have the gun butt facing left, in other words, I draw this gun with my left hand. In the rare cases that I would carry a third handgun (really if it is that bad, where is my 870 or .223); I have carried my trusted High Standard DM 101, .22mag in its Galco wallet holster. Unfortunately these guns are long out of production but a Beretta Mod. 21 in a similar holster