How do you guys deal with being told that you are a "good little slut"?

I've been told that I am a "good little slut" multiple times by different men. I am not really sure how to react, it seems like it's not fair to me. It's not like I am "asking for it", I just don't know what to do in this situation. I don't understand why it would even bother me, and if I am being a "good little slut", it really isn't.