text: take a loofah and scrub the area to be shaved more coarsely than you would if it were soapy and you were just washing your body.  the scrubbing will prevent as many ingrown hairs, and will also allow the area to be smoother longer, because you're scrubbing away dead skin, and shaving at the new skin level.  it might not sound like that big of a difference, but we're talking like 2 bonus days here, depending on how fast your hair grows.