good question
let's face it, one of the biggest trends in porn in the last few years is step-daddy this and step-daughter that, etc...before that porn was toying with incestual taboo relationships until they cleaned it up with the ''step-'' prefix...
That genre is popular for a reason...it's taboo. In our hyper-sexualized society, we need edgy stuff to get off...I saw a super hot blonde Anna Rey Horny (look it up if you can find it) say in a solo masturbation scene, while pointing her ass at the camera, ''You can use any hole you want Daddy!"....well that was enough for me, I exploded. The sexual male brain has some evolutionnary "dark corners".
With the right person in the right context, yeah sure, why not. Never happened to me in real life, and I would not ask for it because i am kinda too shy, but I'm sure if the right girl would say it by surprise at the right time, i would explode again. You just have to be aware that it is role-play only.
While on the similar topic, in my experience, only a small percentage of providers talk dirty..."do you like my tight little pussy? " or "you feel so go inside me", etc it can be a real turn on, but it can<t be too fake.