I teach yoga at my jiujitsu gym, so I HAD to have the Murder Yoga rash guard. I’m between Med and Lrg on shirts/jackets, and I ordered the Med so it would fit close. Unfortunately, the Med was tight under my arms and I couldn’t wear it comfortably. I contacted customer service, got an RMA and a shipping label quite easily, and returned the Med. Nation Athletics sent me the Lrg and it fits great! And, my teammates and yoga students all think it’s hilarious.