When my kids were babies, I always nursed them while they got their
immunizations.  They never cried, just maybe looked up with a little squeak,
then carried on nursing.  The first time either of them cried during an
immunization was when my son was 3 and my husband took him and he said he
cried for a long time.  It seemed to me the obvious thing to do at the time
and I can't see any problem.  I once saw a mom in the hospital nursing her
baby while she changed a diaper.  That's what you call good coordination!
Miriam