like this, pull out a C-Note and tell her you want to watch her play with herself and cum before you start your second round. Regardless of how weak their English is, all Kgirls speak "C-notes."  Lol   Don't let it leave your hand unless she says, "Yes."  If she doesn't understand, take her hand, put it on her pubes and tell her you want to see her cum by herself.  The veterans and older girls will likely not be at all embarrassed and happy to take the extra hundred.  Newer younger girls are another story, but for some, the offer of the extra hundred may help them overcome their embarrassment.  

 
Expecting her to include it on spec that she MIGHT get a tip is disingenuous since you already know it's not a normal menu item.  

I would start by showing her that you are interested in continuing the intimacy by making out with her and caressing her body rather than just shoving a bunch of cash in her face. She's a human being, not a vending machine. After that I would try to communicate that I am interested in watching her touch herself by touching myself. You can take it from there.

Korean girls are really sweet by nature. Besides the fact that I gave then cash up front almost all of my experiences have felt very natural. It's really unfortunate how many guys in the scene view them as objects that exist merely for their pleasure and receptacles for them to dump their loads

but as long as you ask respectfully I don't think any will get really upset with you about asking. You might want to just observe how they are acting during the first part of the session -- do rub at all while you're giving DATY? If so I don't think they will mind the request at all.

 
While I'm not certain the phrase is quite right you could try asking "jawihae bon hal kkeyo?" (자위해 본 할 게요?). That won't sound like Jaw ee hay but more like cha (but verysoft ch with j sound) we ae (the h here will be soft too) bon (o like in bone not bond) Hal kayo (k as in kate). If that is not understood you can use it to lead into moving her hand to where you'd like to see her pleasure herself.  

 
You can also look into a translator app (Naiver's is probably better than Google's) like in the link below. Also on the Apple store if you use iPhone.

In the bay area, I would guess that Niya, Kira, Bora or Zuri would likely be receptive to your request

Success!!

Hi Folks,

I wanted to thank everyone for their input and feedback.  I recently had a session with a kgirl that spoke limited English.  While getting a massage after round one, I asked her if should would touch herself.  She said looked at me confused and said, "huh??".  I grabbed her hand and gently put it over her kitty.  She smiled and knew exactly what I was asking for.  She went to town, and I was quickly ready for round 2!!  Thanks again for everyone's help.

MT