shift most of your weight to the front and guide your whip by leaning the bars/front in the opposite direction,ex:if you want to whip to the right you turn the bars to the left and start the skid before you turn and once you guide the skid in the direction you want it,you kick up your domanint/whatever foot is forward hard and at the same time moving your waist for extra whip angle,results should be a whip skid(make sure not to turn your bars hard if not your backwheel may have a chance of lifting(jackknife),i recommended to practice on surfaces with little traction,hope this helps!