Mammary intercourse describes a sex act, performed as foreplay or as non-penetrative sex, that involves the stimulation of the male penis by the female breasts. Commonly, this sex act involves the man placing his penis in the woman's cleavage and thrusting between her breasts, while the breasts are squeezed around the penis for additional stimulation.

Mammary intercourse can also be combined with fellatio. Researcher Austen Woods, in a study of the condom usage habits of New Zealand's sex workers, said that they offered safe sex alternatives to clients who refused to wear a condom.

Woods quoted a sex worker saying that mammary intercourse was one alternative used, because she claimed it felt to clients like sex without a condom when performed by a woman with large breasts.

It should be noted however that mammary intercourse is not truly safe sex, as some STDs can be transmitted by skin-to-skin contact. When mammary intercourse continues to the point of ejaculation, the semen can land on the breasts, face, or in the mouth of the woman. A slang term for the appearance of semen landing on the woman's upper chest, neck, or shoulders is a "pearl necklace".

Several slang terms refer to mammary intercourse, such as boobjob, titfuck or titty fuck in the United States, as well as tit wank or French fuck in the United Kingdom. The Japanese sex industry uses the term paizuri (from oppai, a slang word for breast).

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 sex education and sexual experimentation of adolescents may feature intercrural sex in the interests of avoiding pregnancy or preserving virginity . In 1987 the Shere Hite report on female sexuality found that some adult women reported being able to achieve orgasm through stimulation of the clitoris by the penis, including via intercrural contact. A variation on this practice is known in Japan as sumata.

Intercrural intercourse (termed diamerizein, "to do it between the thighs") was common in the Ancient Greek system of pederasty, where anal sex was considered demeaning to the, usually younger, receiving partner.

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.

Frot is a slang term (ult. from the French verb frotter, "to rub") describing a form of male/male non-penetrative sex, where two men engage in the rubbing of erect penis on erect penis — typically while fully nude and in a frontal embrace that allows simultaneous kissing, and often with a shared understanding that the frot is not merely foreplay to some other type of sex, but will instead continue until both men reach orgasm and ejaculation.


Owing to its non-penetrative character, frot has the safe sex advantage of drastically minimizing transmission of HIV and other infections without the inconvenience and expense of condoms and special lubricants.

Coined sometime in the late 1990s, the word frot (rhyming with "dot") was shortened from the term "frottage" (rhyming with "massage"), a more generic and unisex term for various types of non-penetrative genital rubbing.

Frot can be enjoyable because it mutually and simultaneously stimulates the genitals of both partners as it tends to produce pleasurable friction against the frenulum nerve bundle on the underside of each man's penile shaft, just below the urinary opening of the penis's "head".

An artificial "lube" may be applied before or during frot, and the use of such lubricant may be particularly advisable if one or both of the men is circumcised. Although it's essential to avoid oil-based lubes with latex condoms during any form of penetrative sex, virtually any non-allergenic lubricant is suitable for frot.

Subjectively, fans of frot report that the high degree of "erotic symmetry" inherent to frot can help induce a feeling of "deep sexual connection" without the need for physical penetration, and also bring about a greater sense of emotional intimacy than is suggested by terms such as "mutual masturbation" or "heavy petting."

And many frot advocates assert that this symmetry will also tend to generate a strong sense of shared masculinity and reinforce a feeling of "equal partnership" for a male/male couple.

(More controversially, some "frot radicals" have made the tendentious claim that anal sex between men must necessarily leave the receptive man feeling both emasculated and degraded in comparison to the penetrating man.)

Since frot is a non-penetrative sex act, the risk of passing a sexually transmitted infection (STI) that requires direct contact between the mucous membranes and pre-ejaculate or semen is greatly reduced.

Notably, HIV is among the diseases that require such direct contact, and is therefore very unlikely to be transmitted via frot. On the other hand, frot can potentially provide an "invasion" opportunity for a few pathogenic organisms that need only skin-to-skin contact.

In this category are the viruses causing genital herpes and genital warts, either of which can, in some cases, lead to serious health problems. At the same time, it should be understood that all of these "casually transmissible" diseases are just as likely, if not more so, to be transmitted during male/male anal intercourse as during frot.