Rock climbing harness over the work trousers and put the pump in the chalk bag or on a carabiner? Nobody will bat an eye.
When I am pocketless or lacking a waistband (as one is when wearing a dress) I like the leg holster … which works well until it falls down as you are making a very public entrance somewhere. Maybe need to combine it with a garter belt? Ladies’ lingerie as a diabetic fashion statement … good for women, excellent for men. Again, no eyes batted for sure.