How do I become more confident and less shy about sex.

I'm not shy talking about sex or expressing my opinion. I enjoy sex and the pleasure as I get from it. I make jokes and I have a very dirty mind but when it comes to sexual activities between me and my Boyfriend. I'm shy and embarrassed about it. And sometimes that's a turn-off for him. I want to know ways where I can overcome my shyness and embarrassment. So i can be more confident, while I do sexual activities with him.