I took some runway modeling classes many years ago and I've been to a few auditions.
I remember one of their photographers instructing me on how to model with my hands. The photographer had a female assistant who asked me to pose with my index and pinky fingers slightly up, while relaxing the remaining fingers. They wanted me to make horns with my hands, basically. I fudged it so bad they gave up one me. Ha ha! Take that with a grain of salt, or whatever it's worth.