The process of kicking someones skateboard while they are riding. Usually this is done subtly while sitting on a chair or bench, hence the name Lax Kick - Relaxed Kick. This usually results in the rider getting castrated.
Lad 1: "Oi, brah! Lets lax kick this fucker cos we run this joint"
Lad 2: "Yea broo. lets fuck that skater up cos they dont deserve to live"