Dirty Talk

My boyfriend and I have been together for over a year and yet I am not comfortable enough in my own body to even take off my shirt during sex. I am very self conscious about my breasts. They are very small and I have no confidence whatsoever so I never take my shirt off. I know it bothers him but I can’t get over my self consciousness. Recently he’s been trying to talk dirty to me. I just can’t seem to tell him anything back even tho he asks me to. How do I come out of this shell I’m in? I want to give him what he wants but i am very self conscious/ shy person when it comes to the bedroom. Any help? :(