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. IyengarPranayama teaches the aspirant to regulate his breathing and thereby control the mind.
B.K.S. IyengarFeeling the movement of movements is wandering to the past or future. Living in the movements of movement is being in the present.
B.K.S. Iyengar