French kiss
A French kiss, also known as Cataglottism or a tongue kiss, is an amorous kiss in which the participants' tongues extend to touch each other's lips or tongue. A "kiss with the tongue" stimulates the partner's lips, tongue and mouth, which are sensitive to the touch and induce physiological sexual arousal. The oral zone is one of the principal erogenous zones of the body. The implication is of a slow, passionate kiss which is considered intimate, romantic, erotic or sexual. The sensation when two tongues touch, also known as "tongue touching", has been proven to stimulate  endorphin release and reduce acute stress levels. French kissing is often described as ‘1st base’, and is used by many as an indicator of what stage a relationship has reached. Extended French kissing may be part of making out. Etymology. A French kiss is so called because at the beginning of the 20th century, in the English-speaking world, the French had acquired a reputation for more adventurous and passionate sex practices. It originated in America and Great Britain. In France, it is referred to as "un baiser amoureux" ("a lover's kiss") or "un baiser avec la langue" ("a  kiss with the tongue"), and was previously known as "un baiser Florentin" ("a Florentine kiss"). The Petit Robert 2014 French dictionary, released in 2013, added the French verb "se galocher," slang for kissing with tongues. The informal English term "frenching" also means french kissing, as does the Quebec French term "frencher." Disease risks. French kissing carries moderate risk of HPV. The possibility of contracting HIV from French kissing is extremely low as transmission would require open wounds. Centers for Disease Control and Prevention considers transmission of Hepatitis B via French kissing to be an unlikely mode of infection, however deep  kissing that involves the exchange of large amounts of saliva might result in infection if there are cuts or abrasions in the mouth of the infected person, especially if they have a high viral load. Occasionally syphilis can be passed through prolonged French kissing, but this usually requires contact with an active lesion. French kissing is an unlikely mode of transmission of infection by gonorrhea.