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. It is known as a titfuck 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).
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.
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".
Since mammary intercourse 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 mammary intercourse.
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- Austen Woods (1996). "Safe sex and parlour work: condom use by women parlour workers in and out of work". in Peter Davis. Intimate Details & Vital Statistics: AIDS, Sexuality and the Social Order in New Zealand. Auckland University Press. pp. 125–127. ISBN 1869401395.
- Bacarr, Jina (2004). The Japanese art of sex: how to tease, seduce, & pleasure the samurai in your bedroom (illustrated ed.). Stone Bridge Press. p. 150. ISBN 1880656841, 9781880656846.
- Constantine, Peter (1992). Japanese street slang. Tengu Books. p. 110. ISBN 0834802503, 9780834802506. "One of the more hazardous oppai [japanese slang word meaning 'breast'] concoctions is the red-light-district expression paizuri, literally 'breast-urbation'."