Mating Dance?

I just put my male and female Hoggies together for the first time. The female is experianced but I do not think the mail has ever mated. The female is doing some kind of twitching thing as she rubs on him and he is rubing on her. They have not hooked up yet and are not showing any signs of aggresion, but this twitching thing is odd. Has anyone ever seen this before?

I just put my 2 hogs together yesterday for the first time as well, and saw the same thing! The male is being persistent and showing alot of interest, but the female isn't playing nice and keeps doing the twitching thing. Anyone know something more about this?