I have not seen any K-Girl offer Greek.
Even when offered a substantial up-charge they all decline.
Any idea why?
But they will allow FIA, TUHA in fact liberally and even enjoy it; or at least pretend to, I mean they don't complain, or yank your hand off.
but no Greek if if you are medium sized.
Any clue?

The girls that openly advertise are usually always prepared (pre cleaning prep) ie Jahee Nabi etc.... I am a magnum so greek is very difficult to get an authorization for the back door pass. I am super gentle and have extensive practice with several ex gf's. Cuban Betty denied me access based on size alone. Now Ive had greek with a few Kgirls that dont even offer it. One being Candy who has since retired back to Korea. If you have the right game and right moves its available more than one might think. But back to your original question I think many just dont have the experience. It takes practice relaxing and mindset to take it in the rear. Many girls once theyre into it orgasm big time.

There are very few kgirls offering it. In the bay right now we have exactly one resident girl offering it officially after it being the worst kept secret for years.

Then there are touring girls like Nabi and Pepsi whod offer it.  
And the rest is very very ymmv and UTR.  

 
I think greek is one area where I feel like I always have to use caveats with kgirls. Ie, they're best service value by far except if you're into anal. Then it's slim pickings. Also all girls officially offering greek offer bb greek which can be dangerous to some as anal sex generally is less safe. And they might not want to see these girls at all.  

 
Outside kgirl world greek is fairly common for a service-oriented provider.  

 
What do kgirl lovers generally do if you really want to bang someone in the bunghole? Do you guys just go for a kgirl anyway or find someome else? Or both? Indies /corg/amps?

to offer Greek.  However, most Thai girls offer it on a YMMV basis.  There are few Thai agencies around these days after the big multi-State bust of their network several years ago, but sometimes Thai girls will turn up at Kgirl agencies and it's worth an ask, but there will be an upcharge.  

 
As my reviews show, I see a lot of Agency Thai girls in London when traveling a few times a year on business.  Most offer Greek for the asking, but expect a good tip after.  Keep in mind that most all Asian girls who have Greek on their menu are YMMV.  It's always subject to them seeing how much sausage you're packing before they give the final okay.  For years, the gold standard for Greek in LA was Yoona, but I believe she retired a few years ago.