French Kiss

A French kiss is a kiss, usually romantic or sexual in nature, in which one participant's tongue touches the other's tongue and usually enters his or her mouth. It is also known as tongue kissing.

French kissing stimulates the lips, tongue and mouth, which are all areas very sensitive to touch, and the practice is considered to be pleasurable, highly intimate, and sexually arousing.

Studying animal behavior, Thierry Lodé, an evolutionary biologist, argues that the French kiss has a real function: to explore the sexual partner's immune system via the saliva. Initiating the sexual desire, the French kiss allows the partners to avoid inbreeding.

According to Wordorigins.org, the term "French Kiss" dated from at least the 1920s but doesn't know exactly who coined the phrase.

Like all human behavior, kisses have both a genetic component and an environmental component. Humans need strong emotional bonds with other people, and part of this bonding is brought about by physical touch. It is in our gene.

Our hands and lips are so sensitive, physical touch to these areas stimulates a greater feeling of touch than other areas of the body. So it's not surprising that hands and lips are used quite often to communicate affection between people.