What are my Macaw Parrots really doing? Weird beak motion?

I've had two of my Macaw Parrots since around December. We're very POSITIVE that one is a male and the other is a female. Please explain well for me to understand,only 12 years of age(: But anyways, they were in their cage (like always) but outside in my backyard and after I was done feeding them I watered the plants in my backyard. After I was done, I walk over to them and see the two parrots doing some weird beak motion/movement. It was EXACTLY like this http://www.youtube.com/watch?v=ujEcPbENqgw it was hard to a better video of them doing the exact thing so I'll just use that one. If you were closer, you'd see that the female was the bottom beak and the male was the top beak.. While they were "beak locked," they jerked their heads up and down quickly like how they did it that video link. It's a little hard to see and I just found that video quickly on youtube. After she (the female macaw) saw me standing there,she stopped for a few seconds until the male decided to.. invite her to do it again ? He "invited" her to do it again by doing it solo,LOL. He was doing it by hiself, jerking his head quickly in one direction to show her he wanted to do it again. So I guess she accepted or something and they did it again and I saw some of their salavia dripping from doing that. This is the FIRST time I've seen them do it in 8 months of having them. They've also seem to be getting along more today, and I saw her rubbing her head against his body,letting him scratch her head with his beak. Usually they'd bite eachother.. So my question is,what are they really doing? Were they mating or something?