Rob, you ask, "Why is it recommended for moms to offer both breasts during a
feed?  If milk is made continuously during a feed, shouldn't a baby stay on
the first breast until completely satified? Why should the baby
want the second side? Does the milk flow slow down as the
feed continues?"

Your instincts are good!  The baby Should stay on Side A until he or she is
finished.  But not because milk is made continuously during a feed.  (Milk is
made continuously around the clock---during feeds and between feeds.)  The
baby should "finish the first breast first," as Chloe Fisher says, because the
baby has the ability to balance its intake of fat and calories best if the
grownups leave the length of feeds up to the baby.  Once the baby has finished
the meal on Side A (fore-milk to hind-milk, or soup to nuts), the baby can
decide whether to start over again with soup from Side B.  If she doesn't want
Side B, she's had a full-course meal from Side A, so it's No Big Deal.

The milk flow Does slow down as the feed continues.

The reference I like best to explain this is Woolrich and Fisher's article
"Colic, 'overfeeding,' and symptoms of lactose malabsorption in the breast-fed
baby: a possible artifact of feed management?"  Lancet, 382-384, 1988.  I
probably re-read that article every year, just to get the picture clear in my
mind.  There are graphs showing the variation in milk flow rate, fat content,
and fat intake through a one-breast feed that lasts 23 minutes.  There is also
a graph that shows the baby's cumulative volume intake and cumulative fat
intake.  They do not follow the same curve!

If you send me your snail address, I'll mail you a copy.  I just used that
article for an in-service with my WIC staff and for a lecture in a university
class I teach.  I wish every person who advises moms about breastfeeding would
commit those graphs to memory.

Peace.   Chris.