It's a simple technique to butterfly a bird, but when it comes to turkey, you're going to need some real elbow grease. I knew I wanted to DIY my first time around, but next time, I'll definitely ask my grocer very sweetly to do it for me. This works up a sweat!
All you want to do is remove the backbone and break the breast bone to the turkey lies flat. If you want to try it yourself, follow the steps on the How to Butterfly a Turkey
for more info!