Dirty Talk

I know this may sound weird but with my ex I was really good at dirty talking. Fast forward and I am with my current boyfriend of almost a year and a half. He can dirty talk all day long while I just freeze up for some reason idk why! It's not a problem in our love life I just wish I didn't freeze up. Also I am more in love with my current boyfriend than my ex so I know that's not the reason. Any advice?