Nice! You will get to know your snakes signs when she is ready to eat. Most of mine all do the same thing. Instead of our cruising at night or being just curled up, they'll have their head poking out the hide, lifted slightly off the ground and very aware of everything around them. This to me is their ambush pose. They have always had a quick strike and good eat when I've introduced a rodent at that point. The head in the S-shape thing is only right before they strike or if they are fearful or cautious.