My 642 goes in the left inside zippered pocket of my Bratwear vest. I have two. One gray. One black. The pocket is padded and made for a gun. This is my standard carry in warmer weather.
Or: In a left hand OWB (J- Fr) made by Milt Sparks at 8 o'clock, just behind my spare mag. pouch for my primary which is at 4 o'clock IWB. The slot is 1 3/4" for my 1 1/2" belt so I don't have to fight to get it on and off! Stays in place just fine.
Or: Uncle Mike's pocket holster--left pocket.
Or: In my right side pocket of my heavy coat or parka when it's zipped up when I'm walking with hands in pockets. You could say that the 642 is actually the primary and P220C under the coat is the secondary gun. Of course, with a little warning and an unzipped coat, that is easily reversed again.
One of those methods will work no matter how I'm dressed. Each has it's place. I'm beginning to like the left hand Milt Sparks a lot. Only drawback is going somewhere where it's necessary to take it off and put it back on. Like the gym where I undress and dress.
Much easier to put on my VM2 on the right side, clip my Bladetech on the left, and slip my Uncle Mike in the left pocket. Have done it many times right next to people (by appropriately turning away) who never had a clue. Then I'm ready to rearm myself from the lock box as soon as I get to my car. Do I carry the BUG with me into the gym when I work out? Well, that's still my secret.
I'd be really careful. You have to decide how safe valuables are in the locker in your gym.