It's often more complex than just the throttle. Any given surface has a level of traction but better riders always get more from it.
Look at some video of pipeline in the ssdt. I'd say on this section body position is as important as throttle control. You need to maintain momentum and that is about having enough weight over the rear, absorbin the bumps to keep the rear wheel on the ground, picking the right line and throttle control.
Practicin figure eights is good throttle control practice as mentioned. However to get good traction there's a bit more to it.