The only thing I could suggest is wear your belt just a tab bit looser so as to pull part of your coat between the belt and your pants. Or just wear a sweater with a hooded sweat shirt over that, it's what I did until I got my drop leg.
That or give the gun to the dog, train him to shoot on command and hope he doesn't spot a rabbit or cat on your walks.
Seriously, just get the drop leg holster. You'll be glad you did, I was.