Get them naked!

"First things first. Girls, when I give you a command while you are hypnotized you are to reply with 'Yes Master'" he commanded

"Yes Master" they all said in unison.

"Perfect. Now girls, take off your clothes"

"Yes Master"

The girls began to disrobe. It was easiest for Yang, sho simply slipped her dress off her shoulders and let it pool at her feet. Meanwhile, Pyrrha and Coco were taking longer, with Coco's intricate clothes and Pyrrha's armor.