There are a few things to keep in mind. Unless the spanker is a ditch digger, his or her hand alone shouldn't be hard enough to cause permanent damage, fraternity paddles are a different matter. Your safest bet for spanking without maiming is going to be the spankee's fleshy buttock cheeks. Most people think the tailbone is located just below the small of the back when in reality it is found an inch or two below the beginning of the buttock divide.