When just taking a leak, I dont unbutton my pants, I just use the zipper, no problem. When doing the number 2 I remove the holstered gun and place it on top of the toilet lid or whatever is available. But be carefull to not forget it. That actually happened with one of the security officers at the Capitol recently, went to take a dump and left their gun in the stall for the next person to find. lol
I work with a guy who found one laying beside a toilet.