The main thing that really helps create this uneven stance through your turn is weighing back and compressing your back leg before your turn. This helps in multiple ways. When you shift your weight to your back leg, the front of your board slightly lifts out of the water, which frees up the rail to wrap around without catching. When you compress your back leg before your turn, you also create leverage, so that when you’re pushing through your turn, you’re able to push harder as you extend your back leg out.
As you start to wrap around, you also want to pull your head and front arm towards the white water with your back arm and shoulder following and creating that emphasis at the end of your turn.