Start with a rock-solid erection and take a sharpie and draw a ring around the base. Next start at the midpoint and draw up the shaft and then down the other side till you meet the ring at the base. If you want to measure from the sides you can draw another line up one side and down the other. Next you need a ruler or cloth tape measure and starting at the base ring you want to measure up to the inch mark and put a line with your sharpie. Then move up an inch and do the same. Continue until you get to the tip. Count the cross lines and you have an idea what you are working with.