Irrumatio
Irrumatio is a form of oral sex where someone thrusts their penis into someone else's mouth, often with the intention an inducing a gag reflex and forced vomiting, in contrast to fellatio where the penis is being actively orally excited by a fellator. The difference lies mainly in which party takes the active part. By extension, "irrumation" can also refer to the sexual technique of thrusting the penis between the thighs of a partner (intercrural sex). In the ancient Roman sexual vocabulary, "irrumatio" is strictly a form of oral rape ("os impurum"), in which a man forces his  penis into someone else's mouth, inducing vomiting for sexual gratification. The act of irrumatio with forced vomiting has become increasingly prevalent in online pornography, and has turned into a well-known pattern in the sex entertainment industry, because of its shock effect and as a form of humiliation and degradation. Etymology and history. The English noun "irrumatio" or "irrumation" and verb "irrumate" come from the Latin "", to force receptive male oral sex. J. L. Butrica, in his review of R. W. Hooper's edition of "The Priapus Poems", a corpus of poems known as "Priapeia" in Latin, states that  some Roman sexual practices, like irrumatio", lack simple English equivalents". There is some conjecture among linguists, as yet unresolved, that "irrŭmātio" may be connected with the Latin word "rūmen, rūminis", the throat and gullet, whence 'ruminate', to chew the cud, therefore meaning 'insertion into the throat'. Others connect it with "rūma" or "rūmis", an obsolete word for a teat, hence it would mean "giving milk", "giving to suck". (Compare the word "fellō", which literally meant "suck (milk)" before it acquired its sexual sense.) As the quotation from Butrica suggests and an article by W. A. Krenkel shows, "irrumatio" was a  distinct sexual practice in ancient Rome. J. N. Adams states that "it was a standard joke to speak of "irrumatio" as a means of silencing someone". Oral sex was considered to be an act of defilement: the mouth had a particularly defined role as the organ of oratory, as in Greece, to participate in the central public sphere, where discursive powers were of great importance. Thus, to penetrate the mouth could be taken to be a sign of massive power differential within a relationship. Erotic art from Pompeii depicts "irrumatio" along with "fututio", fellatio and cunnilingus, and "pedicatio" or anal  sex. The extant wall paintings depicting explicit sex often appear to be in bathhouses and brothels, and oral sex was something usually practiced with prostitutes because of their lowly status. Craig A. Williams argues that "irrumatio" was regarded as a degrading act, even more so than anal rape. S. Tarkovsky states that, despite being popular, it was thought to be a hostile act, "taken directly from the Greek, whereby the Greek men would have to force the fellatio by violence". Furthermore, as A. Richlin has shown in an article in the "Journal of the History of Sexuality", it was also  accepted as "oral rape", a punitive act against homosexuality. Catullus threatens two friends who have insulted him with both "irrumatio" and "pedicatio" in his "Carmen" 16, although the use could also mean "go to hell," rather than being a literal threat. In modern English, the term "fellatio" has expanded to incorporate "irrumatio", and the latter has fallen out of widespread use. Likewise, "irrumatio" might today be called "forced fellatio" or "oral rape". Another synonym for "irrumatio" is "Egyptian rape" or simply "Egyptian"; this goes back to the time of the Crusades when Mamluks were alleged to force their Christian captives  to do this. Ethnology. "Peruvian erotic pottery of the Mochica cultures represent a form of fellatio in the vases showing oragenital acts. See the vases illustrated in color in Dr. Rafael Larco-Hoyle’s "Checan" (Love!), published in both French and English versions by Éditions Nagel in Geneva, 1965, plates 30–33 and 133–135. The action should really be considered "irrumation"".