Female Behaviour when introducing a new pig

Question
Hi

I have recently bought a little 2 month old pig (Brandy) for my 5 month old pig.(Honey) I gradually introduced them over a week and they seem to be gettin on great. The only problem is, is that Honey keeps swaying her hips and purring constantly around her. Brandy doesnt do anyting about it. She's too young I guess. It only stops when they stop to eat or lie down together. It's been going on now for 3 days. When i first introduced them face to face, Honey mounted Brandy and started humping away for a minute. Once that was over they were fine. But it's just this swaying/purring thing! Honey has been sexed by a vet so im sure shes a female. They aren't showing any signs of aggression though which is a good thing.
Any reason why Honey is doing this and will it ever stop?

Thank you x

Answer
Felicia,
  Sorry for the delayed response. As long as you are positive that they are both female, than that is just a normal dominance behavior. The purring/hips swaying is, although fairly uncommon, also a dominance behavior. Here is a link to a website to make sure that they are both female, vets and pet stores often make mistakes when sexing them.
 http://cavyspirit.com/sexing.htm