Doing a roller on a big board as a SUP is not natural.
The best way to do it is to truly use the paddle all long the time of your move.
So, when you do your bottom turn, put you weight on the shaft to increase the turn ability of your board.
When you hit the lip, paddle on it to accelerate and turn faster.
Then pay attention to the next drop to avoid the nose dive.
Rider : l’Ours on the 12′ No Friend Attitude.

Source : Team GONGSUP, pro active stand up riders.