Lifting them, palms up, over her head as if she were trying to get them as far away from herself as possible also gives a peculiar body language signal. If you place them on the same level as the moving part at least for a few moments, you direct traffic to that area and the motion and effort will not be wasted. Do not bother yourself with a fancy hip shimmy if you are creating Frilly-Lou Birds with your hands held above your head. The dancer's hands and her arms too, should act strongly as energy projectors and receivers and need to fulfill that function. Great dancers use energy with power and care.
Poor dancers use and abuse it, flailing away at the audience with unbridled motion.
Their hands twirl and rotate though the air constantly as if they were perpetual motion machines. This characteristic movement is what I refer to as Frilly-Lou Bird Hands. They are fancy, but more than a bit silly. In contrast, the great dancer understands dialogue with her audiences. The constant transfer of energy through focus, in which hands and arms are used as projectors and receivers, creates a relationship between performer and audience.