The terms proximal (from Latin proximus, meaning 'nearest') and distal (from Latin distare, meaning 'to stand away from') are used to describe parts of a feature that are close to or distant from the main mass of the body, respectively.
But, with Citrucel and/or Metamucil you can start with one teaspoon mixed in water or juice. If you have diarrhea don't use the preparation with artificial sweeteners. Use the one with sugar. I think artificial sweeteners (some of them) might cause more diarrhea.
IBS: IBS certainly can be a cause of chronic diarrhea, although there are many other possibilities also. A good initial approach would be to increase the amount of fiber in your diet and take a fiber supplement such as Metamucil daily for several weeks, to see if it helps, before embarking on a work up.