At CCOm there is no dress code. You may wear whatever you want.
In the OMM lab, they want you to wear comfortable clothes; scrubs, sweats, t-shirt etc.
At CCOM, we do OMT through the clothes. No one is ever required to be partially exposed. As DOs, we are supposed to be able to palpate and feel through anything. In fact, our first OMM lab was trying to feel objects inside of bags of various thickness, and trying to figure out the object. Once they told us a story about a legendary DO that would put a piece of hair in the phone book and keeps turning the pages until he can no longer feel it through the pages. Everyday that number of pages increased. He kept doing it to get better at palpation and touch.
At CCOM, everything is done through the clothes.