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.
Metamucil is a fiber supplement made from psyllium. It is designed to add bulk to the stool and so help waste travel smoothly through the digestive tract. It may be marketed as a bulk laxative because it adds bulk to the stool. Psyllium, the main ingredient in Metamucil, is a soluble plant fiber.