Manipulating the shape of the nose of your mat is a great way to generate more "hold" while moving across steep or bumpy sections.
At 8:41 Mike Cundith finds himself behind George G with the wave threatening to pass him by. He pulls up on the outer pontoons to create more rocker and a deeper belly shape in the nose. The added drag in the nose allows the mat to climb back up into the power of the wave and accelerate forward.
It's a case where adding drag adds speed, which is counter-intuitive by conventional surfing standards. You can apply this move riding any wave on any day...try it!