Anilingus
Anilingus (also analingus) is the oral and anal sex act in which a person stimulates the anus of another by using the mouth, including lips, tongue, or teeth. Colloquial names include rimming, rim job, and eating ass. It may be performed for pleasure or as a form of erotic humiliation. People may engage in anilingus for its own sake, before anal fingering or penetration, or as part of foreplay. Studies indicate that anilingus is a rare sexual practice between women.
Anilingus can involve a variety of techniques to stimulate the anus, including kissing or licking; it may also involve the tongue moving around the edge of the anus or up and down the insides of the cheeks of the buttocks, and in and out of the anus.
Facesitting may sometimes involve anilingus along with cunnilingus.