This drill is quite fun and I use it a lot in my short game practice routine to consolidate a few of the fundamental techniques that you need. The only way you can play what is effectively a medium height pitch shot with an 8-iron is to keep the loft on the club by keeping the hands low and soft.
You need to get nice and low by flexing the knees and leaning the shaft back. (You probably need blade irons to do this properly). Keep the hands out of the shot as much as possible and feel the club working to the left.
Think about trying to get the ball rolling up the clubface. If you can do this with an 8-iron, then changing to a 56″ wedge on the course is going to feel easy.
Keep the hands low and soft with the shaft leaning back and feel the club working to the left