cunnilingus (n.) Look up cunnilingus at Dictionary.com
1887, from Latin cunnus "vulva" (see cunt) + lingere "to lick" (see lick (v.)). The Latin properly would mean "one who licks a vulva," but it is used in English in reference to the action, not the actor. The verb ought to be *cunnilingue. As an agent-noun, Fletcher has lick-twat (1656). Gordon Williams ["A Dictionary of Sexual Language and Imagery in Shakespearean and Stuart Literature," 1994] writes that Nicolas Chorier's 17c. "Satyra Sotadica" "relates how Gonsalvo of Cordova, as an old man, would lick his mistress's middle parts, which he called, with a geographical pun, going to Liguria" (from Latin ligurio "to lick").
Cunnilingus was a very familiar manifestation in classical times; ... it tends to be especially prevalent at all periods of high civilization. [Havelock Ellis, 1905]
Dutch slang has a useful noun, de befborstel, to refer to the mustache specifically as a tool for stimulating the clitoris; probably from beffen "to stimulate the clitoris with the tongue."