Intercrural sex (from "inter-" and Latin "crura", legs), also known as femoral/interfemoral sex/intercourse, is a type of intercourse variously regarded as penetrative and non-penetrative sex, in which a male partner places his penis between the other partner's thighs (often with lubrication), and thrusts to create friction. It is therefore a type of Irrumatio.
The historian K.J. Dover wrote about this extensively in his book Greek Homosexuality (1977), from which current theories on the subject of Greek male-male sexuality are largely derived. Joan Roughgarden refers to standing face-to-face intercrural intercourse as the "gay male missionary position" of ancient Greece in a section of her recent book Evolution's Rainbow that draws heavily on Dover.
Intercrural sex is sometimes known as the "Princeton First-Year". The term may refer to a system by which upperclassmen helped new students assimilate to university life in exchange for sexual gratification. A similar system was present at Oxford University, hence the synonym "Oxford Style". Students at both Oxford and Princeton may have been imitating homosexual practices in ancient Greece, depicted by authors such as Plato and Aristotle.
Intercrural intercourse has been proposed as an important part of the sexual lives of a handful of notable historical figures known or thought to have been homosexual or bisexual. According to his biographer Richard Ellman, Oscar Wilde was introduced to intercrural sex by Robert Baldwin Ross, and it appears to have been his preferred activity, even over oral sex.
Shaka Zulu is speculated to have encouraged intercrural intercourse among his troops to "create intimacy and loyalty". Quotes attributed to the Cynic philosophers regarding Alexander the Great, made both during and after his lifetime, seem to presume intercrural intercourse between Alexander and Hephaestion.
Similarly, comments made by a bed mate about Abraham Lincoln's thighs led to speculation of intercrural intercourse between the two in C.A. Tripp's recent The Intimate World of Abraham Lincoln.
Though some modern Christians and Jews have made the argument that intercrural intercourse is not specifically condemned by Leviticus 18 or 20, it has been subject to various historical sodomy laws and religious restrictions; one of the questions a young man entering confessional during the medieval period would be asked was "Have you fornicated with another male between his thighs? By this I mean, have you ever put your manhood between the thighs of the other, and through vigorous movement ejaculated semen?"
Intercrural intercourse appears to have been common during the medieval era anyway, a contemporary document titled the "Altercatio Ganimedis et Helene" (The Debate of Helen and Ganymede) depicts Greco-Roman mythical figure Ganymede describing the "slippery thighs of a boy" as superior to the "stink and gaping looseness of the female cave".
Intercrural sex is still quite common in some communities. A 1997 report on the sexual health needs of MSM in the Calcutta suburbs found that 73% of men asked engaged in intercrural intercourse, though the frequency varied based on demographic factors: only 54% of sex workers, 50% of lower income men and 40% of Muslims reported intercrural sex; while 82% of Hindus and 88% of middle income men reported engaging in it.
A similar study from South Asia reported that intercrural sex was tied with anal sex as the second most preferred sex act of gay men, making it more popular than oral sex and frot.
