Gonneke,
the reason I understand nipples get erect, is to provide a locator clue for 
the infant   who is nuzzling up to mother's breast and smells milk, but wants 
confirmation that this is where the nipple is. Baby rubs his mouth or face 
against the breast at the location of the strongest smell of milk, the nipples get 
erect and provide a tactile target. baby opens mouth, mother pulls him in, 
and he gets reward of something to suck, and then, of course, milk. They do not 
need to stay erect. The fact that they may   during their constriction stop 
milk flow may help the baby get into position first. 
Fritzi Drosten, RN, IBCLC
SF Bay area
USA

             ***********************************************

To temporarily stop your subscription: set lactnet nomail
To start it again: set lactnet mail (or digest)
To unsubscribe: unsubscribe lactnet
All commands go to [log in to unmask]

The LACTNET mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software together with L-Soft's LSMTP(R)
mailer for lightning fast mail delivery. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html