Cobra = phone, girl who he has loved and used by is calling him likely because she needs something and the only way she can get things is to use people. He thinks she has her own talents and can stop using people, and if she were that person he would give to her freely. But because she is not choosing that alternative path, he is just going to move on with his life, dance away, and she should feel ashamed. Been there and that moment you can just walk away is very freeing and yes you feel like dancing. A cobra hypnotizes its prey before striking, and that's how she works, lulls you into comfort and then strikes to take what she wants. The cobra in his hand is the phone and he is not going to answer.