asking SO about BDSM

okay, we've kind of talked about it before but it was more like he likes to be tied up and I'm all cool with that but I'm definitely not a dom and just recently learned the label for what I am. (I'm a brat. at least according to the test, that's the name for it, the definition they give absolutely fits me.) Now, my thing is I really want to have an in depth discussion about it and see how we can work it out where we both get what we want but I'm still kind of shy around subjects of sex and what I want out of it even though we've been together for 6 years. There are things that still embarrassed me and things that have only been happening for maybe a year (69, oral on me mainly). So, the question is, how do I bring it up after so many years and not be all weird about it. I'm pretty sure at least one of the fantasies I have (consensual non consent) he will have a definite problem with but I won't know for sure until I ask but I'm scared to ask. Any help?