I am afraid to rain on your parade, @Avalon, but the enjoyment out of nipple sucking that you see in Bel Ami movies is just a fantasy.
I don’t think so. I have met a lot of Czech boys, and virtually none of them has sensitive nipples. BTW, that includes your favorite Czech, @Avalon. I have very sensitive nipples myself, and they didn’t really understand it: they were actually amazed at my reaction, and many said they wished their nipples were erogenous.