I see a while board dedicated to this but do not know what it s.  Urban dictionary does not help.

... it meant Korean girl?

Usually you are dealing with a booker when contacting a k-girl.

END OF MESSAGE

It's an FAQ over there.

Go to K-girl forum.
Look for the big blue "Search" tab. [Top 10] [Search] [New] [Overview]
Then do this search:
 
search for [ What is a K-girl ] [Exact phrase]
author [      ] (leave blank)
day range [ 999 ] to [    ] (leave blank)  
 
and you will retrieve many prior discussions of this topic.  

Here are some:  

http://www.theeroticreview.com/discussion_boards/viewmsg.asp?MessageID=4475&boardID=113&page=#4475

http://www.theeroticreview.com/discussion_boards/viewmsg.asp?MessageID=6302&boardID=113&page=#6302

http://www.theeroticreview.com/discussion_boards/viewmsg.asp?MessageID=4158&boardID=113&page=#415