The act involves the two parties acting as a cat or as a dog, the female is usually the cat and the male is usually the dog.
The objective of the dog is to 'jump' on things whether it be a couch or objects on the ground but also to jump on the cat (hence why the male is the dog as they are most sexually aggressive) also the dog looks at the cat with puppy dog eyes whenever it wants the cat to play with the dog more.
The objective of the cat is basically to purr every time the dog pats her, but as cats get tired of things very quickly if she gets patted for too long she will scratch the dog .
there are many variations to this depraved act but those are the basics to how Cat and Dog is to be done.
Michael: At least he gets to play Cat and Dog with her!
Tim: Cat and Dog? What the faaaaak?