Telling him what you want without being awkward

My boyfriend is really into bdsm but he hasn't done anything like that with me for months now. It's been very vanilla sex and the sex doesn't last as long as it use to, he seems to always want quickies. I want some good long bdsm sex sessions but I don't know how to ask him for it in a non awkward way. I really suck at talking dirty too so I just don't know how to tell him. Plus he has been really tired from work so I'm sure he just isn't down for all the work that goes into it so I would kind of feel bad if I even asked. Advice please?