I enjoy dirty talking, and do it in some form in most of my sessions.
I start with light comments such as "good girl", "love the sight of your young face sucking me". Depending on how comfortable the SP is, she might respond favourably to it, such as "yes sir", and I go even dirtier.
On the rare occasions I'm with a 18 or 19 yo, I've found thrill in a lot of "teen" talk, replicating things I hear in porn, "love your little teen body".
I once got into it with an 18 yo and I was overwhelmed by excitement when she responded to my dirty talk with "you like that 18 year old teen pussy?" while I was pounding her so hard in doggy style, it made me pound harder than I thought I was able to. So exciting for the two of us.
Once, after dirty talking throughout the session, I asked the SP whether I could pay an extra for insults, she was into it and a lot of "slut" and "whore" references.