the more pressure you put into a tube, the faster it's going to figure out how to get out.
If your MTB tire is at 50psi and your Road bike tire is at 150psi, there will be a dramatic diff. as to how much air is lost in time.

That's part of why i think you gals should check to see if you aren't overinflating the tires for your weight specs.

and my DH taught me a cool trick. make sure the valve is at the TOP of the wheel when you attach it to the pump. SO when you are ready to stop and pull it off you are pulling/pushing DOWN; so it's easier.