Anilingus

Anilingus, from the Latin cūlus + lingus (anus + lingere, to lick), and alternately spelled analingus, is a form of oral sex involving contact between the mouth of one person and the anus of another. Anilingus is also formally referred to as anal–oral contact and anal–oral sex. Anilingus can be performed by people of all sexual orientations, and may be used for personal pleasure or as a form of erotic humiliation. The term was coined by sexologist Richard von Krafft-Ebing in his book Psychopathia sexualis (1886).