While I suppose "realness" is always preferred. I don't mind a lil staging, once it's believable. Alas though, a lotta porn actresses tend to overact. And that can admittedly make things awkward.
I honestly just always prefer a lil dialogue over nothing at all though. So even if the acting is a bit cheesy, I like that over them just saying nothing.
My favourite dialogue, and this is really hard to come by I've found. Is when the girl is just being cute and casual about it, talks about her need to pee and what she drank that made her have to pee. Maybe a lil "mmm" or "that feels so good"