I'd recommend NOT using the terms we use her when messaging a POT SB.
BCD
P4P
PPM
BSC
POT SB
These should stay confined to this board.
Let me repeat that: These should stray confined to this board!
When talking to a POT SB, whether via email, text or face to face, I use terms like "back to my place for some indoor fun", or "adult time", or "nakey-fun", or whatever way you want to say it without sounding too explicit. Saying "I'll fuck you for $300" is probably not going to work out. And saying "BCD" and then having to explain it is almost as bad. Give them the illusion that this is more romantic, BF/GF sex and not a transaction-based deal, and they can rationalize that they are not hookers.
Talking in terms of spending an afternoon or evening, or the whole day together is also preferable to saying 2 hours for $400. SB's can do some math, even if it is through their "Princess Lens" ("I am a Princess and my pussy is priceless!").
If pressed before she agrees to meet, I usually respond like this:
"I usually like to go out for a nice meal or maybe do something fun like wine tasting, shopping or a movie. Then we can go back to my place for some adult fun. For that, I'd like to help you cover some bills and other expenses, usually $200 to $300 or so. What do you think?"
Once you've laid out that framework, she will generally start to negotiate within that framework:
"Sounds fun, but I'd probably need 400, is that ok?"
or
"Why not skip the meal and we can go straight to the fun? I'd be ok with 500"
...and so on. Of course, you MUST counter these if they are above your budget, but you now have control of the process, you have established that the sugar only comes with the sex, and you have avoided the "I'm worth it" bullshit rational.