I also say with backbends, you have to be cautiously bold. Not carelessly bold. You have to descend to the dictation of the spine. You cannot command from the brain to do the poses. As you play with a child, guarding the child from injuries, similarly you have to play in backbends, guarding your spine.
B.K.S. IyengarYou must do the asana with your soul. How can you do an asana with your soul? We can only do it with the organ of the body that is closest to the soul - the heart. So a virtuous asana is done from the heart and not from the head. Then you are not just doing it, but you are in it. Many people try to think their way into an asana, but you must instead feel your way into it through love and devotion
B.K.S. Iyengar