"That's a nictitating membrane," Kurama answers, lifting his head again now that he can breathe without hating life. "If you weren't born with them, you need surgery, a transformative spell, or a body-sharing bargain with someone who does to get them."

Body-sharing. He'd almost forgotten that he can change forms at will again, and he can't remember any of the reasons why that might be a bad idea, so he does. It's easy as anything now, easy as breathing, and then he can feel a light breeze on his ears and suddenly bare arms and everything is wonderful.