Do you mean the "PC" {P/uboC/occygeus) muscle?

The following link is one of many that will provide the requested information.

http://www.mwsexual.com/readingroom/articles/kegel-exercises.htm

The exercise can be practiced throughout the day when convenient. One way to begin is to interrupt the flow of urine several times when going to the bathroom. Even if you do not need to pee, you can practice the exercise while sitting at a desk at work, walking, or sitting in a chair at home.

Another link
http://www.phoenix5.org/Basics/treatsides/incontinence/kegelOSU.html