What do I do??

My female cat was fixed about a month ago. Yet she still rolls and acts like she is in a heat cycle. That doesn't bother me, but she keeps trying to get our male dog to do her. She goes over and sticks her ass in his face for him to lick her and rubs all over him and follows him everywhere. How do I get her to leave him alone? He doesn't like it and gets mad and bites her and I'm worried he will hurt her by buying her too hard.