Coyotes love wallowing in, or rubbing on, smelly items — usually a dead rodent. They indulge themselves, unrestrained, luxuriating and taking pleasure in something the rest of us humans find rather repulsive. Dogs do it, too. Humans don’t have a handle on why this is so much fun. In this case here, the coyote is rubbing her back on something she likes, rolling back and forth, and stretching at the same time, trying to get as much “coverage” as possible.