I don't know if I would call Crystal from GW a milf since milf hunters would find she's a bit young looking for that, but she's not 20 any more and that ass is generous. She is fabulous at dirty talking. I doubt slow milking would be a challenge for her, just ask.
Recently, another poster
@Royyy007 revealed that Lucy from BW does pretty intense dirty talking. I would not call her a milf, since you might not get what you expect if I did, but she's past 30 for sure. And slow milking? No probs for a veteran mpa like her.