In this strike, you want to step past the subject. As you move past the subject, you want your striking hand to either drop down or to remain where you were positioned before stepping past the target you are stepping off line from the attack.
Your non-weapon hand reaches out behind the target in preparation to secure the target for the strike. You want your body and shoulders to open up in preparation for the strike.
You now want your arms and hands to collapse down on the target. Picture your body and hands closing like a clam.
As you drive the stick into the target, you want to drive all the way through the target and attempt to touch your other hand on the other side of the target.