I have had a few boyfriends that loved it. I was somewhat surprised at first but then I have noticed that more of them actually did like it. I don't even for a second think that it is anywhere near the sensation that we feel but, it feels good to them anyway.
We do it if he prefers it. Some girls don't get aroused when their nipples are caressed. I have only meant one guy who liked his nipples sucked. It was weird to me at first because I always looked at it as a erogenous spot for only woman.