Graham well as the other comment mentions on that particular wave you may just be too far back on the board in general to pull it off. While your foot should be on the tail pad for turning, it does not always stay there. I have the same issue, LOCATION, that you do. I ride small gutless slop all day too. When I'm playing around on my kids 7' micj fanning soft top, my feet (including back foot) are much further forward away from the tail. It allows the board to plain more, therefore generating more speed, and thus making the stacking easier.
If you have a bosu ball practice your stance on that with the idea that you need to move your back foot forward and backward freely. On a bosu with no forward momentum it will be more difficult to stack solely on the front foot, so hold onto a chair back or counter top and practice only being over that front leg and moving your back foot forward and backward while still maintaining the stacked front leg.
Commented on Ok lets try this again, here is the y...
15 Jul 03:32
I don't know about anyone else but when I click link it says video is private and won't let me watch.