For some people, depending on build, it is easier to conceal a gun in an IWB holster in the 1:00-2:00 position with a loose, fairly long shirt over it. That way it avoids the problem of the lop-sided appearance when having the right side of your waist look bigger than the left side when carrying at 3:00 in a belt holster. A CZ 2075 or Para Warthog, or similar sized piece can be concealed pretty well that way. Also a snubbie revolver, such as a j-frame .38 or a Charter Arms Bulldog. Just be careful when standing at the urinal so the gun doesn't get "indecently exposed".