First, I love the name!
While you have received much advise on "technique" here there are four areas where this issue may originate and you must evaluate each area to find the true cause of your backseat issues.
Technique: 4ster and others have addressed this already, it is how you move on your skis.
Equipment: This is the cause for many fore/aft balance issues that gets overlooked but getting your boots and bindings assessed could reveal it not your technique that is the problem but your alignment along the sagittal plane. A good instructor or boot fitter should be able to help you here. Of all the possible causes this one, if it is remedied properly will affect immediate change in your balancing performance.
Physiology: This possible cause stems from poor conditioning. Strengthening the core muscles and the muscles of the legs helps, particularly the tibialus anterior muscle which connects from your big toe to knee and dorsiflexes your ankle. Strengthen this muscle and your ability to remain centered will improve.
Psychology: If the cause is in this area you must change your intent to turn from skiing the fast line slow to skiing the slow line fast.
Find the real cause to improve your balance. You can work on technique all you want but if the cause of your backseat issues is caused by poor equipment alignment your efforts will be futile until you fix the alignment issues. Fix the cause rather than treat the symptom!