Dirty talk?? I'm clueless!

Lauren
Hi, all! My boyfriend recently told me that he likes dirty talk and to be occasionally called "daddy" while having sex. I am a relatively quiet person during sex and have never said a word other than the sporadic "fuck" or "yes". 
I told him I would think about it, as it makes me really nervous. The obvious fear is that I'll say something stupid and he'll laugh at me. 
I guess I'm just wondering how you ladies have overcome the anxiety of becoming more vocal? Or if you were never anxious about it, what are some things that really get your man going?