Shove-it In
Mechanism / Why It Happens
Your body is being carried out of the ramp. Keeping it inside the ramp is more important than rotating the board.
If you attempt the shove-it without thinking about anything else, the middle of the board will ride up onto the coping, much like a rock to fakie. That may be a valid trick in its own right, but it also shows that, in order to hold the nose over the coping, you need to move your body back toward the inside of the ramp.
What to Do
Use a pumping motion to control the direction in which your body is launched.
If you simply ride up the ramp using momentum, your body will be carried out of it, so add a pumping
