Embarrassed to ask but looking for a k-girl for a CFNM (clothed female nude male) appt...

Just let the booker know of your request so they can prep the kgirl.  Actually, this sounds like fun.  I'm gonna for ask this on my next adventure!

I've made special requests before.  Shouldn't be an issue what you are asking for.

I had a kgirl tell me once she had a client come over.  When she looked through the peephole, there was a woman standing there.  The girl called the booker and told her, there's a woman in front of the door.  Booker called back the client.  Client answered and said, yes, it was him (her).  Turns out it he was a transgender, a guy wanting to become a woman (didn't have the "cut" done yet).  Girl lets him/her in.  All they did was talk.  Client just wanted to get some advice about being a girl, finding a boyfriend.  Quite a lonely guy, quite sad, really.  After an hour, paid the girl the fee and left.  

So your request is very pedestrian.  No need to be shy about it.  Get crazy, don't even take off your shoes.