I wish my pictures had looked like that. I think I need some lessons in moth handling! I don't know if you can tell, but I ended up using a still from a video clip of it.
Practise on the Large Yellow Undies, but approach from the front end, first two fingers above and thumb below. Grasp the head end decisively and firmly, but not enough to hurt the moth. You will lose a few scales and hairs. Once held, turn over and gently pull open a hindwing. Copper Undies are quite slippery and it will take one or two to get the hang of it.