Set her up for later

"Luna, you believe whatever I say and agree with whatever I say." Res then gave her a trigger for being put back in a trance then woke up.

"You are in a lot of trouble, young lady!" said Res as he put his hands on his hips.

"Why? What did I do, sir?"

"I'm from the Ministry of Magic, and you are suspected of cheating."

"But I have not!"

"Strip naked to show me you are not hiding anything. Do it right here, right now."

Luna stripped naked then held her clothes in front of her. "See, I'm hiding nothing."

"Do you have your wand on you?"

"Yes, sir."

"Stick it up your ass, leave your clothes on the floor, and follow me." Res waited until Luna did as she was told and then led her to the library where he was supposed to meet Romilda. "I see you love being naked," said Res. "It's OK to be nude. It's more natural, and lets the magic flow more freely. Stay nude as much as possible."

Luna's embarrassment receded and she looked more confident standing their nude.

"Now, I want you to see if you can cast a spell with your wand up your ass. Try to cast a simple spell."

Luna waggled her ass with the wand sticking out of it and said incantations, but she could not cast any spells.

Romilda showed up a minute later with all of her panties. She was shocked to see the naked Luna waggling her ass with the wand sticking out.