Hmmmm... Not to sound paranoid, but when you say she has her nose to the sky and then falls over, is it clumsy and awkward? Or is it sort of a graceful, controlled fall? The reason I ask is she might be exhibiting signs of an RI (stargazing, possible neuro symptoms) but if she's eating well I don't think you have anything to worry about. Just keep an eye out for runny nose, snotty bubbles, and a popping/cracking sound when she breathes.

Alternatively: She's a wee lass and is exploring her tank because BPs are master escape artists, or as you say, she's doing the hungry dance.