If he does try to mount one of the girls in front of you, don't let him do that. Stop him from doing it, because if you let him do that then he thinks he is dominant over you. At least that is what I was told when I first asked this same question.
I could be wrong, but it sounds like he is doing the chicken dance for ya. That is what I call it. In other words it is what my roosters do to the girls when they want to mate with them.