anilingus
noun
ani·lin·gus ˌā-ni-ˈliŋ-gəs 
variants or anilinctus
ˌā-ni-ˈliŋ(k)-təs
: erotic stimulation achieved by contact between mouth and anus
Example Sentences
Recent Examples on the Web All of these could be signs that there’s extra bacteria hanging out down there, which is definitely not ideal for anilingus. 
Lindsey Lanquist, SELF, 12 Mar. 2018
Lindsey Lanquist, SELF, 12 Mar. 2018 Word History
Etymology
New Latin, from anus + -i- + -lingus, -linctus (as in cunnilingus, cunnilinctus)
First Known Use
1949, in the meaning defined above
Medical Definition
anilingus
noun
ani·lin·gus ˌā-ni-ˈliŋ-gəs
variants or anilinctus
-ˈliŋ(k)-təs
: erotic stimulation achieved by contact between mouth and anus