When we had my sweet old cat, Alice, she ignored the dogs, so this "dogs and cats playing" thing is pretty new to me and I'm not sure where to draw the line.
Many years ago, my parents had a foundling cat who used to play outside with my aunt's Jack Russell terrier. They would play tag, they would box and wrestle, but they were the same size and so it was all innocent joy to watch.
Our new kitten, Boo, is nearly grown and probably about 7 pounds of youthful exuberance. She likes the dogs and after an initial transition period where Maddie stalked the cat endlessly, things have settled down and most of the time they all hang out together, quietly enjoying each other's company.
However, the cat likes to play with the dogs. One thing she does, which I don't mind, is stalk the dogs, run up and bat them a few times and then dart off. Jack tires of the game quickly, and Maddie will chase as many times as the cat "attacks." If the cat gets to be too much I'll put her away for awhile and get her to play with her toys, but usually she's fine and I know that this behavior will settle down as she matures.
What I'm not so sure of, though, is the mock "fights" that she and Maddie engage in. I want to make clear that Maddie play-bows for the cat, and she play-barks at the cat (if I had any doubt it was a play bark, Jack settles the question by sometimes getting confused by going over to engage Maddie in a game, only to be disappointed when she ignores him because she's playing with the cat). Maddie has had many opportunities to grab the cat and never once tried to (the cat will even go in the dogs' crates to snooze). So I know it's play, but I don't know if it's safe play or not.
Basically, what happens is Boo will make her "I'll pounce on you!!" fake-fierce face at Maddie and flip on her back, front paws extended. Maddie will bark-bark-bark at the cat, centimeters from her face, and air-snap in her direction with each bark. She's never made contact with the cat. The cat responds by boxing Maddie about the face and ears repeatedly, and even mimics Maddie's play-snaps by snapping her own jaws at Maddie. Then Boo will leap up, charge off sideways with question-mark tail, and have Maddie chase her. Then Boo will find another spot and flip over on her back and start the whole mock-fight thing again.
On the one hand, both animals seem to enjoy their game so much. On the other, I worry that one will get over-excited and Maddie will get seriously scratched (kitty has all her claws), or Maddie will "forget" to self-handicap in her excitement and bite the cat for real, and what would happen if she felt fur in her teeth? Would that tip her from play drive to prey drive? Maddie is not a small Corgi and weighs about 28 pounds, so even when the cat is full grown Maddie will be about 3 times her size.
All advice/input greatly appreciated!