Offer arrived, can I still ask for more?

I want to negotiate but I am afraid they will withdraw. I do not usually post, so bear with me. The hiring manager was friendly and open. What wording worked?

I thanked them and said I was excited but hoped we could talk about the pay. They came back with a bit more.

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.