At the point where the video stopped, you're feet are close to the heel side edge of the board but you're hinged at the hips with your weight over the center or possibly toe side of the board.
I actually just tried this on a bosu ball. Standing upright with my heels close to the edge, the ball was obviously tilted with the edge resting on the ground. When I hinged at the hips and put my weight over the center/toe side it brought the bosu ball level even though my feet were on the edge.
I think you're upper body in that position is keeping the board flatter whereas if you were standing more upright with your feet in that position I think you would have gotten a little more rail engagement. But like Graham said, that board would probably be hard to get on rail in any case.
Commented on Steven Segal ive gone and helped you ...
28 May 12:40
I struggle with generating speed on weaker waves and I am more likely to get stuck behind the section if it's a faster wave when going back side.
I find it helps to look down the line while in the process of the back side take off. You kind of went straight down into the flats before turning your head to look at what the wave was doing.