2006年3月24日 · wo cao ni, its Very commonly in Chinese , personally think that should come from "i fuck your mother's cunt(wo cao ni ma bi)," this, including the derivatives,such like fuck your mam(cao ni ma), fuck your whole family(cao ni quan jia), your mother cunt(ni ma bi), your mam cunt(ma bi), should be the source of Since "I fuck your mother's cunt."