How do I stop punching with my torso and start punching with my hips?

[OMGWTF]

I have a bad habit of punching from the torso, using my torso (obliques) to rotate my hips, rather than using my hips to rotate my torso!

So I have 2 problems, the 1st is I cant rotate my hips on their own, I dont have that control over them it feels natural instead to use my torso to turn my hips.

My second problem is I cant stop using my torso to turn my hips, I cant seem to "turn off" using my torso to rotate.

How do I keep my torso loose and unused so I can take advantage of the stretch reflex in it and get snap in my punches?

How do I gain control of my hips so I can rotate them at will by themselves without the torso?

[OMGWTF]

Any drills I can use to gain direct motor control over my hips?

[greynotsoold]

Break your punches down and do them in slo-motion, starting at the floor. Start with the pivot of the foot that transfers the weight, and turns your hips, and that turns your shoulders, which drives the arm. Watch yourself in the mirror and make sure that your hips get as close to the center line of your body before your shoulders turn; that the shoulder get as close to the center line as possible before the arm moves.
Stand close to the heavy bag, your feet not quite on a line, arms at your side, bent at 90 degrees. Start turning your hips, slowly at first and making sure that you are transferring your weight from foot to foot. For example, pivot inward on your right foot. This will put the weight on your left foot and turn your right hip, which will drive your right fist into the bag. Then pivot on your left foot, and so on. Make sure and turn your hips all the way through and never let your hands get ahead of your hips. As you pick up speed, or want to punch harder, pivot more sharply and turn your hips more aggressively.

[OMGWTF]

Break your punches down and do them in slo-motion, starting at the floor. Start with the pivot of the foot that transfers the weight, and turns your hips, and that turns your shoulders, which drives the arm. Watch yourself in the mirror and make sure that your hips get as close to the center line of your body before your shoulders turn; that the shoulder get as close to the center line as possible before the arm moves.
Stand close to the heavy bag, your feet not quite on a line, arms at your side, bent at 90 degrees. Start turning your hips, slowly at first and making sure that you are transferring your weight from foot to foot. For example, pivot inward on your right foot. This will put the weight on your left foot and turn your right hip, which will drive your right fist into the bag. Then pivot on your left foot, and so on. Make sure and turn your hips all the way through and never let your hands get ahead of your hips. As you pick up speed, or want to punch harder, pivot more sharply and turn your hips more aggressively.

Thats absolutely brilliant advice thanks mate much appreciated, its very clear you know the optimal way to throw a powerful snapping punch!