If you're interested, the hand wave is actually a way of communicating submissiveness. As in - if a Beardie were to enter into another Beardies' territory, they would do that hand wave to indicate that they didn't want to fight and basically announce their inferiority to the other male.
The other funny one they do is the 'head bob' dance they do before mating a female.
“Everybody has a secret world inside of them. All of the people of the world, I mean everybody. No matter how dull and boring they are on the outside, inside
them they've all got unimaginable, magnificent, wonderful, stupid, amazing worlds. Not just one world. Hundreds of them. Thousands maybe.” -Neil Gaiman