Click this link and scroll down a few posts:
https://forum.oneclickchicks.com/show...&page=11&pp=10
And I will tell you why they do this...
A few years ago when I was doing the extended Euopean student travelling thing with a buddy. While in Greece we met some fellow travellers and started hanging out as a group. You know a dozen or so university kids who have not much in common except age, travelling and beer.
To make a long story short, the chix in the group from Australia and Holland were going topless

on the beach and the girls from Canada and the US were not.

After a couple of days the North American girls loosened up and began to remove their tops - most for the first time.
One of the first timers - a large breasted Edmontonian -
burnt the crap out of her nips.

And as I learned, burning your nips is different from burning your tits. Poor girl, she was in agony for the next week and could only wear large t-shirts (borrowed from me and another guy) and lean forward most of the time so the cloth wasn't touching.
I must admit my buddy and I felt guilty because we were leading the group (leecherously I admit

) convincing the North American chix to "let it hang out". You know "Oh come on it's Europe, everyone's doing it, nobody cares." etc etc.
We also felt bad because those North American chix soon covered up again

when the saw the perils of prolonged nipple exposure to the sun...especially for first timers.
That's what I learned...debutantes, use lots of sunscreens - and even then - protect those nips!
Cheers!