Find a cork that fits in teh testers paint bottle. Drill a 1/8th inch hole in it. Take a second cork and "screw" the drill bit into that cork, leaving the bottom of the bit sticking out.
Put the cork with the hole in it into the bottle of paint firmly. Slide teh butt end of the drill bit into the hole. The hole is sealed so the paint will no tdry out.. when ready to mark, pull teh drill bit out, the cork wipes off all excess paint, leaving a tiny dab on teh end of the drill bit. Touch on the queen, and slide it back into the cork/hole
Try it, it will astonish you how well it works and how easy it is to do/use