Another analogy like the sink is the garden hose. I will sometimes tell clients think of a garden hose that is kinked (the breast prior to feed ) release the hose (your letdown) the water comes out forceful and will continue to give water until someone turns it off (baby taken of the breast) Also, I too try to avoid the term "empty breast" I say "milking the breast" adequately and/or correctly. Annette RN,BSN