How exactly do cats play with one another?

My boy is living with my partner who has a female feline. :) Her female usually doesn’t get along with other cats. My boy has been living with them for 3 months now and the two kitties tolerate each other. Actually, he follows her around when they’re outside and she puts up with it. I think that he’s smitten, haha.

My question is, when she crouches down and wiggles her bum, then pounces on him, is that her way of playing with him? When she pounces, she meows loudly (as though she is ticked off)! He either stands there or he runs away. :)

When he tries to play with her, he crouches, then pounces. She freaks out and smashes him on the head (whilst giving out an angry meow).

So, is her version play? Or is she trying to intimidate him (scare him away)?