Dirty talk

So things are amazing between my  boyfriend and I... Over a year and still going strong.
He loves to dirty talk during sex and likes when I do too. I enjoy it as well but sometimes worry that I sound dumb... Or I just run out of things to say all together. He wanted to try on the phone this morning and I completely choked.
In past relationships I was mostly just expected to lay there and be quiet while my hubby got off. It was like I was just there as his sex toy.
So, this is all new for me. Any advice you can offer would be much appreciated!