Although I've never personally had a problem with chafing, I do have a friend that had this issue. The problem always seemed to arise with the use of a particular undergarment. Not only did the area become irritated and red, but it made wearing the garment almost unbearable. At the time, I didn't have very many helpful suggestions for her. She had tried petroleum jelly, but hated it because it was so greasy.
Currently, Lanacane is offering a free sample of their new anti-chafing gel. This gel won't wash off if it gets wet, and glides on nice and smooth. You won't have to worry about your skin rubbing against skin or clothing anymore. In addition, the formula won't stain your clothes like petroleum jelly would.