Breasts are an important symbol of female sexual maturity. They are one of the most important sexually sensitive areas of women and are also the organs that secrete milk and nurture offspring. Breasts are a symbol of motherhood for children; they are objects of beauty and desire for men. Therefore, women in movies, TV, pictorials, and literary works always have plump breasts. Breasts are important sexual organs for women, and they also play an important role in sexual activities, but people often ignore this. The nerve distribution and number of nerve endings in the breast are very rich, and the relationship between the breast and other sexual organs is very close.

During the excitement phase of the sexual response cycle, the first evidence that the breasts respond to sexual tension is the erectile response of the nipple, which is the result of the involuntary contraction of the rich smooth muscle fibers in the nipple after being sexually stimulated. The reactions of the two nipples often do not occur simultaneously, and one may have reached full erection and swelling while the other lags behind. Inverted nipples may protrude from their quiescent state, as if in a semi-erect position. If this inversion is difficult to recover, no nipple reflection will be seen. Should be indicated. ​

A sufficient erectile response can increase the length of the nipple compared with before being stimulated, generally by 0.5-1.0 cm. The reaction can also increase the diameter of the nipple base by 0.25-0.5 cm. Usually, those with large nipples that protrude forward tend to have smaller swelling and erection tendencies than those with normal-sized nipples. It is difficult for nipples to respond strongly to sexual stimulation if they are particularly small, but it is rare for nipples to be particularly small.

A second physiological change during the excitement phase is increased delimitation and expansion of the breast venous tree pattern. If the breast is of sufficient volume, underlying superficial venous congestion will occur, but probably will not become more definite until later in excitement. Larger breasts often exhibit a pronounced expansion of the venous tree pattern. The hyperemia of the breast venous tree usually does not reach the areola area as it expands toward the center.

Nearing the plateau, the actual volume of the breast will increase significantly, which is the result of the congestion reaction of the deep veins of the breast. When a woman in a sexually responsive state has an erectile response, the congestion at the lower part of the hanging breasts is easier to observe. If the woman is in the supine position, the overall increase in breast volume will be more obvious. Obvious areolar congestion can be seen in the late stages of excitement. The degree of expression and occurrence time of the excitement phase reaction vary greatly and often vary from person to person and from time to time. During the plateau phase, the areola adjacent to the erect nipple will also swell, often giving people the illusion that the erect nipple has partially subsided. It is not until the areola swelling subsides during the resolution period that people can again see the erect nipple that has subsided more slowly.

Before a woman experiences the final orgasmic impulse, the size of the breasts of women who have not breastfed can increase by 1/5-1/4 than usual. The breasts of women who have breastfed usually do not show a significant increase in breast volume. This difference in anatomical presentation may be due to increased venous shunting during milk production in the fed breast. Baby sucking increases venous shunting and tends to slow down the hyperemic response of deep blood vessels during sexual tension. Obviously, the increase in breast size under the influence of sexual tension is not only related to the physiological response of blood vessel congestion, but also related to the fullness of the fibrous tissue components that make up the supporting breast lobules. Overexpansion of the breasts, which is common in early lactation, impairs the effectiveness of these supporting fibrous tissues. Therefore, it is understandable that the female breasts after breastfeeding are difficult to respond to sexual stimulation as they should.

After sexual tension reaches a plateau, pink spots often appear on the front, sides, and even below the breasts. In fact, this maculopapular rash first appears on the upper abdomen and then spreads to the breast surface. This vascular congestion reaction on the skin surface is called sexual blush.

There is no specific reaction in the breasts during orgasm. Nipple erection and areola swelling are well established, venous tree protrusions are prominent, the non-lactating breast is significantly dilated from the pre-stimulation baseline, and sexual flushing is well defined. Breasts may even tremble.

The arrival of the regression period is signaled by the rapid subsidence of sexual flushing and the simultaneous disappearance of areola swelling. However, the nipple erection subsides slowly. When the areola swelling subsides, the nipple erection becomes conspicuous again, giving the impression that they have experienced a secondary erectile reaction caused by the influence of new stimulation or the effect of existing stimulation. People call this This illusion is called "false erection".

Generally speaking, the congestion of deep blood vessels in breasts that have not been suckled subsides more slowly, while the congestion in breasts that have been breastfed subsides faster. It is often seen that breast swelling will remain for 5-10 minutes after the climax, and the superficial vein tree on the breast surface can even remain for a long time. Complete elimination of vein tree The erect nipples have fully recovered before regressing to their normal non-revealing state. This persistence of both superficial and deep vascular congestion effects is unique to the unsucked breast and may be due to overexpansion of the areolar venous plexus during the plateau phase. During the resolving phase, overexpansion of this venous plexus results in a slowing of the blood flow that the veins drain into the deeper veins.

The swelling and development of the areola during pregnancy is an early indicator of the effects of pregnancy. A clear distribution of venous trees will appear on the breast surface after one month of pregnancy, and they will remain throughout pregnancy and the postpartum period. Women who are pregnant for the first time will have a sensitive area on the side of the breast, which will expand as the pregnancy progresses. Breast volume will increase rapidly after 3 months of pregnancy, which is the result of a significant increase in breast blood vessels and glands. After receiving sexual stimulation during pregnancy, women who are pregnant for the first time will experience severe breast tenderness during the orgasm stage, especially the swollen nipples and areola. By the second and third months of pregnancy, this breast tenderness will be significantly reduced. Because during the second and third months of pregnancy, when the breasts already show the characteristics of a conical lactation shape, their volume has increased by about 1/3 compared with the non-pregnancy stage, so high levels of sexual tension often cannot make the breast volume further significantly increase. However, nipple erection and areola swelling reactions occur throughout pregnancy.

In the second and third months postpartum, the breast's response to sexual stimulation depends on whether it is breastfeeding or not. If the production of milk is artificially suppressed through hormonal control or restraint and compression, in addition to the erection of the nipple, other sexual response phenomena of the breast will be significantly suppressed, even when sexual tension reaches a plateau. It is not until 6 months postpartum that the breast sexual response of these women can be restored.

Although the breast size of breastfeeding women will not increase significantly during sexual response, they often respond in an unusual way. Many breastfeeding women often ejaculate uncontrollably in response to sexual stimulation. During or after orgasm, milk can overflow from both nipples. This phenomenon is not only seen during sexual intercourse, but also during masturbation. Because the number of observed cases is still small, these phenomena cannot yet be statistically significant.