I did a workshop on dirty talk a few years ago and still have my notes…
Prep - how do they want themselves / their genitalia to be referred to? Ask!
Dirty talk without declaration - just because you say it, doesn't mean you are intending to do it, can just be fantasy.
Keep it open - "What if I...?", "Maybe I'll do..,"
Be non-specific so your person can write their own adventure - "I'm going to run my tongue where you want it most"
Choices - "do you want me to do X or Y?"
Questions -"tell me about a time when you.... how did it feel?"
Recount a scene - "remember when we..,?"
Talk about what you know / your desires - "I'd like to do XYZ to you"
Pauses - don't fill the silence - build anticipation
Noises - little purrs, sighs, moans, laughter (fun!)
Tone of voice- don't have to whisper but speak calmly and with conviction
Listen to erotica - get ideas!
Create your own audio erotica - listen back to it
Talk to yourself - practice - you know what arouses you!
Hope that gives you some tips and ideas 😁