Koko crater was named by missionaries who did not like the Hawai'ian name, Kohelepelepe, which apparently translates as "fringed vagina."

According to a racy legend, the pig demigod Kamapua'a hotly pursued the goddess of fire Pele on the Big Island.  The goddess Kapo, Pele's sister, detached her kohe (vagina) and flung it to eastern O'ahu to divert Kamapua'a.  The trick apparently worked because the pig demigod followed the so-called traveling vagina and left Pele alone.  The vaginal imprint became the crater known as Kohelepelepe.  (Hikers guide to O'ahu by Stuart M. Ball, Jr.)
http://home.hawaii.rr.com/khsc/history.html