I can't lie, I love it. It turns me on and will often do the trick if I'm struggling to cum, or if I go slightly soft for whatever reason. I have asked girls to do it before. Yes it's fake, but so is the whole experience, so I just get lost in it without worrying. I'm a guy who has never had a punt where I forgot I was paying/felt 'chemistry' or the other stuff people sometimes describe. So I'm used to the feeling like I'm in bed with an actress. I can understand how dirty talk could kill the realism if you are into 'normal', somewhat believable sex.
Having said all this, the kind of dirty talk I like is descriptive. Encouragement basically - fuck me harder, give it to me, cover my face etc etc.
Blowing smoke up my arse is different, and I agree that's a huge turnoff - wow your cock so big and all that rubbish. Girl once told me I tasted amazing after CIM and I just felt so unimpressed, embarrassed even. It patronises your intelligence - like does she really think I believe that?