Young Kissing Girls

A kiss is the act of pressing one's lips against the lips or other body parts of another. Cultural connotations of kissing vary widely. A kiss may be used to express sentiments of love, passion, affection, respect, greeting, friendship, and good luck, among many others. The word came from Old English cyssan "to kiss", in turn from coss "a kiss". The act of kissing has become a common expression of affection among many cultures worldwide. Yet in certain cultures, kissing was introduced only through European settlement; prior to this, kissing was not a routine occurrence. Examples of this include certain indigenous peoples of Australia, the Tahitians, and many tribes in Africa.
Kissing is a physical expression of affection or love between two people, in which the sensations of touch, taste, and smell are involved. According to psychologist Menachem Brayer, although many "mammals, birds, and insects exchange caresses" which appear to be kisses of affection (e.g. lovebirds), they are not kisses as humans consider them. Psychologist William Cane notes that kissing in Western society is most often a romantic act and describes a few of its attributes:
It's not hard to tell when two people are in love. Maybe they're trying to hide it from the world, still they cannot conceal their inner excitement. Men will give themselves away by a certain excited trembling in the muscles of the lower jaw upon seeing their beloved. Women will often turn pale immediately of seeing their lover and then get slightly red in the face as their sweetheart draws near. . . . This is the effect of physical closeness upon two people who are in love.