R.J.
I LOVED my nipplesheild. OMG...I had completely forgotten about them. I used mine for 3-4 weeks, and the transition happened via sleep dep, and not being able to always find it at night.
((I got so engorged when my milk came in (each breast was Bigger Than My Head, approx the size of a helium party balloon... the non-mylar kind)... that my son couldn't latch, and then he was allergic to lanolin, so the ordinary nipple ointment was a no-no.))
Gradually my size reduced, over several weeks, and my nipples toughened up. When he woke starving in the night, & I couldn't find the durn thing, he'd eat. Maybe one or two feedings a day for a week or two, and then I lost it and never bothered to find it again.
Remind your friend, the important thing is the milk, not the delivery system. So many women can't nurse at all, and so many babies don't even have a lactating mum (adopted, etc.) that she and her baby are both really really lucky. Who cares about a piece of plastic? :)
R