Physiological response of female breasts during sex

Breasts are an important sign of female sexual maturity, one of the most important sexual sensitive areas of women, and an organ that secretes milk and feeds offspring. Breasts are a symbol of motherhood for children and an object of beauty and desire for men. Therefore, women in movies, television, pictorials, and literary works always have large breasts. Breasts are important sexual organs for women and they also play an important role in sexual activities, but people often overlook this point. The breasts have a rich nerve distribution and a large number of nerve endings, and the breasts have a very close relationship with other sexual organs.

During the excitement phase of the sexual response cycle, the first evidence of increased breast response to sexual tension is the erectile response of the nipple, which is the result of involuntary contraction of the rich smooth muscle fibers in the nipple after sexual stimulation. The two nipples often do not respond in sync; one may be fully erect and swollen while the other lags behind. Inverted nipples may bulge out of their resting state, appearing to be in a semi-erect position. If the inversion is irreversible, no signs of nipple reaction will be seen.

A full erection response can increase the length of the nipple by 0.5-1.0 cm compared to before stimulation. The response can also increase the diameter of the nipple base by 0.25-0.5 cm. Women with large, protruding nipples usually have a smaller tendency to swell and become erect than those with normal-sized nipples. It is also difficult for nipples to respond strongly to sexual stimulation if they are very small, but very small nipples are rare.

The second physiological change during the excitement phase is the increased delimitation and dilation of the mammary venous tree pattern. If the breast has sufficient volume, there will be congestion of the underlying superficial veins, but this will probably not become more pronounced until late in the excitement. Larger breasts often show a more pronounced dilation of the venous tree pattern. The congestion of the mammary venous tree does not usually reach the areola area as it expands toward the center.

As the breasts approach the plateau phase, their actual volume increases significantly, a result of deep breast vein congestion. When a woman is in a sexual response state and an erection occurs, the congestion in the lower part of the pendulous breast is more easily observed. If the woman takes a supine position, the overall increase in breast volume will be more obvious. In the late stage of excitement, obvious areola congestion can be seen. The degree and timing of the excitation 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 the illusion that the erect nipple has partially subsided. Not until the areola swelling subsides during the resolution period can the nipples that resolved later but remain erect be seen again.

Before a woman experiences the final orgasmic impulse, the size of the breasts of a non-breastfeeding woman can increase by 1/5 to 1/4 compared to usual. The breasts of a breastfeeding woman usually do not show a significant increase in breast volume. This anatomical difference may be due to increased venous shunting in the fed breast during milk production. The infant's sucking increases venous shunting and tends to slow the deep vascular congestion response to sexual tension. It is obvious that the increase in breast size under the influence of sexual tension is related not only to the physiological response of vascular congestion, but also to the degree of fullness of the fibrous tissue components that make up the supporting breast lobules. Overexpansion of the breasts is common in early lactation, which can impair the effectiveness of these supporting fibers. Therefore, it is understandable that it is difficult for a woman's breasts to respond as clearly to sexual stimulation after breastfeeding.

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

There is no specific reaction in the breasts during orgasm. Nipple erection and areola swelling are established, venous dendrites are prominent, the unlactated breast is significantly dilated compared to the pre-stimulation baseline, and the sexual flush is well defined. The breasts may even appear to tremble.

The onset of the resolution phase is signaled by the rapid fading of the sexual flush and the simultaneous disappearance of the areola swelling. However, nipple erection subsides slowly, and when the swelling of the areola subsides, the nipple erection becomes prominent again, giving the impression that they have experienced a secondary erectile reaction caused by new stimulation or existing stimulation. People call this illusion "false erection".

Generally speaking, the congestion of the deep blood vessels in breasts that have not been sucked will subside more slowly, while the congestion in breasts that have been breastfed will subside faster. It is often seen that breast swelling will continue for 5-10 minutes after orgasm, and the superficial venous tree on the surface of the breast may even remain for a long time. The erect nipples fully recovered before the venous trees had completely receded to their normal non-visible state. The persistence of this effect of both superficial and deep vascular congestion is unique to unsuckled breasts and may be due to excessive dilation of the areolar venous plexus during the plateau phase. During the resolution phase, this overdilation of the venous plexus results in a slowing of blood flow from the venous drainage to the deeper veins.