Scent rolling is the act of pressing the body against a strong-smelling object or scent. This behavior usually begins with the wolf pushing a cheek against the object, and then sliding on it until the side of the chest has cleared the object. The wolf will likely stand and repeat the process several times on each side of the body.
Wolves commonly perform this behavior with any strong or unique-smelling object within their territory, such as a smelly carcass (food), urine or feces from another animal outside the pack, or any other pungent odor encountered that is not a regular scent within their territory.
Scent Roll by kafilipi on deviantart.com