Intercrural sex (from "inter-" and Latin "crura", legs), also known as femoral/interfemoral sex/intercourse, is a type of non-penetrative sex, in which a male places his penis between his partner's thighs (often with lubrication), and thrusts to create friction.
The sex education and sexual experimentation of adolescents may feature intercrural sex in the interests of avoiding pregnancy or preserving virginity. Shere Hite's 1976 and 1981 research on female sexuality found that some adult women reported being able to achieve orgasm via intercrural contact to stimulate the clitoris. A variation of heterosexual intercrural sex is a practice known in Japan as sumata.
Male homosexuality 
Intercrural intercourse was a common outlet for pederasty in ancient Greece, because anal sex was considered demeaning to the receiving partner. The Ancient Greek term for this practice was diamērizein ("to do [something] between the thighs").
The historian Kenneth Dover wrote about this extensively in his book Greek Homosexuality (1978), from which current theories on the subject of sex between men in Ancient Greece derive. Joan Roughgarden refers to standing, face-to-face intercrural intercourse as the "gay male missionary position" of Ancient Greece in a section of her book Evolution's Rainbow (2004), which draws heavily on Dover.
Intercrural sex among men who have sex with men (MSM) is sometimes known as the "Princeton First-Year", the "Oxford Style", the "Oxford rub", the "Ivy League rub," and is included in frot. The synonyms referring to schools are used to describe "horny young men during the long, cold winters away at all-boys schools," especially in the 19th century.
Intercrural sex 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 sex 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 sex between Alexander and Hephaestion. Similarly, comments made by a bed mate about Abraham Lincoln's thighs led to speculation of intercrural sex 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 sex is not specifically condemned by Leviticus 18 or 20, it has been subject to various historical sodomy laws and religious restrictions. Intercrural sex appears to have been common during the medieval era; for example, 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 sex, 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.
See also 
- "interfemoral intercourse", Dictionary of Sexual Terms, Sex-Lexis.com.
- Hite, Shere (2004). The Hite Report: A Nationwide Study of Female Sexuality. New York, NY: Seven Stories Press. p. 277-284. ISBN 1583225692, 9781583225691 Check
|isbn=value (help). Retrieved 2 March 2012.
- Constantine, Peter. Japan's Sex Trade: A Journey Through Japan's Erotic Subcultures. Tokyo: Yenbooks, 1993, p. 75. ISBN 978-4-900737-00-6.
- Dover, K. J. (1978). "The Prosecution of Timarkhus". Greek Homosexuality. Cambridge, Massachusetts: Harvard University Press. p. 98. ISBN 0674362616. OCLC 3088711. Retrieved 10 December 2012.
- Dover, K.J. (1977). Greek Homosexuality. MJF Books.
- Roughgarden, Joan (2004). Evolution's Rainbow. Berkeley: University of California Press.
- The Oxford English Dictionary, s.v. "Princeton"
- Piepenburg, Erik (February 2006). "What's Rub Got to Do With it?". Out. pp. 74 and 76. Retrieved 2011-02-18.
- Salon.com Sex | The Oscar Wilde centenary
- Gevisser, Mark (1999). Homosexuality in Africa: An Interpretation. New York: Basic Ovitas Books.
- Fox, Robin Lane (1994). Alexander the Great. Penguin Books.
- Tripp, C.A.; Jean Baker (2005). The Intimate World of Abraham Lincoln.
- MCC - Practice Of Safe Text
- Project MUSE
- Boswell, John (2005). Christianity, Social Tolerance, and Homosexuality: Gay People in Western Europe from the Beginning of the Christian Era to the Fourteenth Century. Chicago: University of Chicago Press.
- Summers, Claude J., ed. (2004). "Europe: Medieval". glbtq. glbtq, Inc. Retrieved 10 December 2012.
- "needs assessment of males who have sex with males in Calcutta and its suburbs" (PDF). Naz Foundation International. 1997. Retrieved 26 October 2009.
- Pre-marital intercrural sex known as soma in Zulu tradition
- Dan Savage on Abraham Lincoln and femoral intercourse (third letter)