There are lists of these to be found (http://www.punterlink.com/modules.php?name=Terms), but the essential starters for ten are:

CIM – Come in mouth. Oral sex to completion
Escort – What most independent prostitutes like to be known as.
Fluffy – A rose tinted view of the business. All the girls are angels, all the punters are gentlemen. Sorry, not true. There are lovely ladies out there, but there are also some not so nice ones, just as there are punters who are nothing like as nice as you. This is a business like any other, and has all sorts of people in it, good, bad and ugly. Just keep a sense of proportion.
GFE – Girl Friend Experience. This usually means she’ll kiss.
Incall – Her place or her arranged incall flat.
Outcall – Your place or hotel
OWO –Oral sex without a condom.
PSE – Porn star experience. Lots of noise, probably signifying very little!
Punter – John, trick, client, appointment – in other words YOU. A man who visits escorts. Also,
WG – Working girl = escort