Took dozens of pictures while throwing the tennis ball a few days ago, and I thought this was the most interesting of the ones that were at all in focus. (There was one really incredible one of Sheba with her mouth thrown back over her back, wide open, showing all her teeth, with the ball a short distance above her mouth. It was similar to the one above, actually, but she was more artfully posed. It was also too out of focus to be useful.)
Having her chin scratched rates pretty highly, but I think chasing tennis balls or her glowy ball is pretty much Sheba's favorite thing to do.