Talking during sex

My s/o is very amazing in the bedroom in every way and he is also very verbal while we’re doing it. He’ll say thinks like “I’m big?” or “Call me daddy” and a bunch of other things. Today he told me that he wants me to be more verbal when we do it because I don’t say much but when I try to it’s like I get super shy and stuck not knowing what to say which sucks because I really do wanna talk dirty back to him. Any tips on what I could say to him while doing it?