Sex is like math: Add the bed, subtract the clothes, divide the legs, and hope you don't multiply. With both subjects you should always be prepared so that you are not taken by surprise or left with unintended consequences. Both sex and math start out rocky because you are dealing with the unknown and you do not have a lot of knowledge or experience. As you practice you will get better at it, gaining an understanding that can be invaluable when dealing with numbers or matters in the bedroom. Multiplication can be prevented by adding the right variables, making sure that you end up with the right results instead of the wrong answer.