This is a phrase frequently used by English-speaking males when they can't understand what the hell the Japanese are saying. Used in conjunction with “Oh” this is said after the japanese (mostly males) start pretending to masterbate, saying "ooki hando partii!" or "Australian Bigger, but Japanese quality better." This means that people are a little scared of the Japs and usually say "Piss off blood oval eyes!"
Nathan; Aussie Male: Where's the Train Station?
Yasumi; Jap 1 (male): Do you have an ooki chinko? (Big dick)
Nathan: Umm....do i know you?
Koki; Jap 2 (male): Do you remmeber my name? I am Koki.
Rory; Aussie Male 2: Eto........(japanese for umm).
Yasumi and Koki: OOKII HANDO PARTII!
Angus; Aussie Male 3: Rightio.......
Koki: Do you remember my name?
Yasumi: Australian Bigger, but Japanese quality better.
Aussies run away....
3 Months Later
Nathan: Your name is Oh koki!
Angus and Ross (Aussie Male 4): Rightio.........Crag muff muff!
Angus: I figure Oh Koki! I'm exclaiming my annoyance or confusion at our situation.
Ross: Whatever. Eat crag gyuunyuu.
This means that the Japanese then say "Do you remember my name?", a question which haunts the victim forever.
Angus: Crag makes me feel like I'm in Japan, he's such a koki.