For this specific skip, called Pause Whip, you basically get to the front of the truck, then using the movement ability that boosts the truck, launch and crash into the truck in front of you. You have to pause at just the moment you crash, you should hear an explosion as soon as you pause. Then just unpause and if done perfectly you should go flying. Its very inconsistent, this took me around 20 minutes. its just about getting the timing of the pause and the luck of flying at where you want to go.