The bridge pose is usually accomplished while coming down from the shoulder stand pose. The spine experiences a reverse bend and the neck pressure is relieved. Holding the bridge is beneficial for the back and abdominal muscles. Entering the pose and exiting it also helps develop a more flexible spine.
The first step to performing the bridge pose is to lie on your back and hold your feet together while you keep your knees bent. Try to lift your hips as far as possible by placing your hands on the lower back. Your head, neck and shoulders should remain on the floor as you arch your back.
The bridge pose is used when coming our of the shoulder stand, but a flexible back is required to complete it safely. While in the shoulder stand - reverse the pose movements until you come out of the shoulder stand pose. Bring your left leg down, then your right leg, one at a time. Maintain the pose while inhaling deeply for a few times. Take one deep breath and go into the shoulder stand and then release the pose and come out of it. In time you will notice that lowering both legs simultaneously is also possible. This is a difficult pose if you are lacking spinal flexibility, but it is achievable if you are willing to invest some time into practicing it.