The dime thing is to get you to tilt or push your pelvis forward so as to get your pelvis/hips centered over the board's width/waist wise. But also tighten your abs, straighten your back and sink in your knees. Otherwise, beginners tend to ride hunched over and stinky but, i.e., counter balanced with their but hanging over the heel edge, their shoulders hunched over the toe edge and they are bent over at the waist. The dime thing is to get you to align or stack your ankles, hips and shoulders by tighening up your core...especially when in a netural position/stance. Then when you are turning toeside...you hump...its the dime thing. And when you go heel side you dump.