Solicitation
Photo courtesy of http://www.flickr.com/
In these two pictures, these are examples of solicitation. They are distance-reducing postures. The cat on the left is rolling, as you can see, trying to solicit play, and the one on the right has the tail up approach. The ears of the cat are up and forward; the tail is up, the body is forward. They're willing to approach another person or animal, and then there may also be rubbing behavior. It is usually companion housecats that use the rolling to solicit petting or play.