A philosophy and common practice in the Pilates method is when the spine is worked in extension it's important to stretch in flexion. Neck Pull is very similar to Roll Up with a deeper challenge on the Powerhouse with the hands behind the back and adding a hinge with a lengthened spine.
Sit up tall
Extend legs opened hips width apart
Place hands behind the base of the neck
Inhale sit up tall on the mat
Exhale round over the thighs bringing forehead to knees
Inhale sit up tall and hinge back to a 45 degree angle
Exhale curl tailbone under and roll back on the mat
Inhale roll right back up and repeat
Lie back in the center of the mat.
Opposition is key throughout this exercise. If you are having a challenge rolling up with the hands behind the head, lengthen arms in front of body.