Just filmed this today, will prob add to the OP. Starting the vid with straight back posture, sticking my gut in to get my head down and the curve in my back. This feel might help some rather than saying, get your tailbone under you and tilt the neck down. The head/eyes are tilted down because of the flexion of the cervical spine. Again you do this by engaging your abs, almost like doing a crunch or if someone was doing to punch you in the stomach.