Spice things up in sex?

I've been with my boyfriend for over a year. The sex is great and we always try new things because we're both freaks and we love it but the one thing that always kills me is that IM TOO SHY TO DIRTY TALK DURING SEX. Idk what's wrong with me. With everything I'm fine. But what can I do to fix this problem??? And what are things to say while dirty talking