A small bottle with seemingly swirling colours inside it has a tiny handwritten note written with instructions written on in swirling, loopy letters. First pick your creature, apply the tint to the exterior of the creature while chanting the change you wish to inflict. This will allow your creature to change it's pose or even if you're lucky it's colour if other colour verietys are known.
*made of the feathers of a Purvia given under moonlight