In some cultures breasts play a role in
human sexual activity. Breasts and especially the nipple are one of a woman's
erogenous zones. They are sensitive to the touch as they have many nerve endings; and it is common to press or
massage them with hands or
orally before or during sexual activity. Some women can achieve an
orgasm from such activities. Research has suggested that the sensations are genital orgasms caused by nipple stimulation, and may also be directly linked to "the genital area of the brain".
[46][47] Sensation from the nipples travels to the same part of the brain as sensations from the vagina, clitoris and cervix. Nipple stimulation may trigger uterine contractions, which then produce a sensation in the genital area of the brain.
[47] In the
ancient Indian work the
Kama Sutra, light scratching of the breasts with nails and biting with teeth are considered erotic.
[48] During sexual arousal, breast size increases, venous patterns across the breasts become more visible, and nipples harden. Compared to other primates, human breasts are proportionately large throughout adult females' lives. Some writers have suggested that they may have evolved as a visual signal of sexual maturity and fertility.[49]
Many people regard the female human body, of which breasts are an important aspect, to be aesthetically pleasing, as well as erotic. Research conducted at the Victoria University of Wellington showed that breasts are often the first thing men look at, and for a longer time than other body parts.[50] The writers of the study had initially speculated that the reason for this is due to endocrinology with larger breasts indicating higher levels of estrogen and a sign of greater fertility,[50][51] but the researchers said that "Men may be looking more often at the breasts because they are simply aesthetically pleasing, regardless of the size."[50]
Many people regard bare female breasts to be
erotic, and they can elicit heightened
sexual desires in some men in some cultures. Some people show a
sexual interest in female breasts distinct from that of the person, which may be regarded as a
breast fetish.
[52] While U.S. culture prefers breasts that are youthful and upright, some cultures venerate women with wrinkled, saggy breasts, indicating mothering and the wisdom of experience.
[53]