thumb|The earliest example of intercrural sex in an artwork; it, according to the author of Greek Erotica Martin F. Kilmer, depicts "the position most commonly adopted". In modern terms, it might be regarded as [[frotting. Webster's Dictionary defines intercrural sex as an act in which one partner "plac[es their] penis ... between the other partner's [closed] thighs ... [and thrusts] to create friction". Synonyms include coitus interfemoris, thigh sex and interfemoral sex.
Kang Tchou of Cambridge University notes Dover's definition is similar to the idea of "heavenly love" articulated by Pausanias that "encourages a stable life-long relationship between the boy and the man and enhances the intellectual development of the younger boy".
History and modern practice
thumb|left|180px|Pedarastic intercrural Sex. Fragment of Cup. 550 - 525 BCE.
thumb|right|180px|Intercrural sex between [[Zephyrus and Hyacinthus. Attributed to Manner of Douris Painter. 500 - 450 BCE]]
Ancient history and the Middle Ages
thumb|right|180px|Intercrural sex between a winged [[eros and a boy. Style resembles Douris Painter. 490 - 480 BCE]]
Intercrural intercourse was a common manifestation of pederasty in ancient Greece; young men were forbidden from having sex with older men in a manner beyond intercrural. It has been associated with Eromenos, although its prominence in such a relationship is undetermined and anal sex may have been more common. Intercrural sex was not exclusively executed by homosexual men; by the early-AD era, it fell out of practice as sex with women became more encouraged in Greek society.
Intercrural sex has been depicted on artworks such as vases, where they were called "courting scenes", and was much discussed by writers. After the 5th century BC, visual depictions of it were sparse and almost exclusively found on black-figure pottery. Zeno of Citium and Aristophanes have been said to reference the act; the latter was the first to document intercrural sex being practiced in a heterosexual capacity. Aeschylus' play Myrmidons features the implication of adult men engaging in the act. Joan Roughgarden refers to intercrural intercourse as the "gay male missionary position" of Ancient Greece.
Historical sodomy laws have included intercrural intercourse within their purview. In 15th-century Italy, it was a part of sodomy's infamous reputation; in renaissance Venice, capital punishment was considered against the partner initiating intercrural sex. Medieval penitentials often highlighted intercrural sex as sinful and gave instructions on ways to repent; early Christianity regarded intercrural intercourse as "more respectable" than anal sex.
Modern history
In early modern English, writers referred to intercrural sex as "rubbing" or "frigging". Literary works and satire depicted intercrural sex, possibly encouraging people to perform the act. Cases of sodomy, such as the trial of Mervyn Tuchet, 2nd Earl of Castlehaven in 1631 that resulted in his execution, occasionally mentioned intercrural sex. Tuchet's case took on significant cultural prominence and informed many people of gay male sexual habits, likely conjuring a cultural perception of intercrural sex as the main method of sex between men. Richard Ellmann believed Oscar Wilde solely performed intercrural sex in the hope he could consequently declare his innocence against the allegation of "posing as a sodomite".