<< Anal Eroticism >>

The anal area (Figures 118f-119f) is erotically responsive in some individuals. In others it appears to have no particular erotic significance even though it may be highly sensitive to tactile stimulation. As many as half or more of the population may find some degree of erotic satisfaction in anal stimulation, but good incidence data are not available. There are some females and males who may be as aroused erotically by anal stimulation as they are by stimulation of the genitalia, or who may be more intensely aroused.

The erotic sensitivity of the anal area depends in part upon the fact that there are abundant end organs of touch throughout the anal surfaces, and in part upon the fact that reactions of the muscles (the anal sphincters) which normally keep the anus closed may be erotically stimulating. Some persons are psychologically aroused while others respond negatively to the idea of anal intercourse, and psychologic factors may have a good deal to do with the erotic or non-erotic significance of such contacts. These generalizations apply to both females and males.

Penetration of the anus may cause pain, and this may intensify the sexual responses for some persons. There are some individuals for whom anal stimulation is definitely erotic, and there are a few who may be brought to orgasm by such stimulation.

The mechanisms involved in such responses are the same as those which account for erotic response to oral, breast, or genital stimulation, and there is no need for special theories to explain anal reactions. It would appear, however, that there is considerable variation in these reactions, probably due to differences in the nerve supply in different individuals, as well as to considerable differences in psychologic conditioning on this point. There is some anal play in some of the marital histories, usually as an additional source of stimulation during vaginal coitus; and there is an occasional instance of anal coitus. However, anal activity in the heterosexual is not frequent enough to make it possible to determine the incidence of individuals who are specifically responsive to such stimulation. Among males who have been stimulated anally in the homosexual, there are only a few who are particularly aroused, and only an occasional individual who is brought to orgasm by such techniques.

The anus is particularly significant in sexual responses because the anal and genital areas share some muscles in common, and the activity of either area may bring the other area into action. Stimulation of the genitalia, both in the female and the male, may cause anal constrictions. Gynecologists frequently observe that stimulation of the clitoris, or of the areas about the clitoris and the urethral meatus, may cause contractions of the anus, the hymenal ring, and the vaginal and perineal muscles. As rhythmic muscular movements develop during sexual responses, and particularly in the spasms that follow orgasm, the anal sphincter may rhythmically open and close. The incentives for anal insertions of various sorts and for anal intercourse lie partly in the significance of these rhythmic responses of the anal sphincters.
An early reference to anal contractions during coitus is found in Aristotle [4th cent. B.C.]: Problems, Bk.IV:879b.

Conversely, contractions of the anal sphincter, whether they be voluntary or initiated by erotic stimulation, may bring contractions of the muscles that extend into the genitalia and produce erection in the male or movement of the genital parts in the female. As a matter of fact, contractions of the anal sphincter appear to produce contractions of muscles in various remote parts of the body, including areas as far away as the throat and the nose. Anal contractions may cause the sides of the nose to flare, and the subject is inclined to inhale deeply—both of which are characteristic aspects of an individual who is responding sexually. When the clinician has difficulty in bringing a patient out of anesthesia, he may start deep breathing by inserting a gloved finger into the anus of the patient. Anal contractions may also be associated with contractions of still other muscles elsewhere in the body; for the contraction of any muscle, anywhere in the body, may develop tensions in every other muscle in the body.

Apparently the abdominal diaphragm is involved when there is anal contraction, for it is very difficult for an individual to exhale as long as the anal sphincters are under any considerable tension.

In brief, anal contractions, perineal responses, genital responses, and nasal and oral responses are so closely associated that one may believe that some sort of simple and direct reflex arc is involved. We do not yet understand the neural bases of such a connection.

Buttocks
Tactile stimulation and heavier pressure on the buttocks may elicit unusually strong responses from the gluteal muscles. These are the largest and the chief muscles on the back surface of the upper part of the leg. Contractions of these muscles reflect, more than any other one factor, the development of the nervous and muscular tensions which are involved in erotic arousal. Some persons, both female and male, deliberately contract these gluteal muscles to build up their erotic responses. Movements of vertebral muscles in conjunction with contractions of the gluteal muscles are the chief means by which the pelvis is thrown forward in rhythmic thrusts during copulation.
Contraction of the buttocks was once considered the mechanism by which semen was expelled during coitus. See Aristotle [4th cent, B.C.]: Problems, Bk.IV: 876b.

Perineum
The perineal area includes and lies between the lower portions of the digestive and the reproductive tracts. The area is essentially the same in the female and the male. The surface of the perineum includes the anal and genital areas and all of the space between. This surface is highly sensitive to touch, and tactile stimulation of the area may provide considerable erotic arousal.

The perineal area is occupied for the most part by layers of muscles, the so-called pelvic sling. Within and on this muscular mass there are nerves, and the area is, in consequence, definitely sensitive when it is stimulated with any sufficiently strong pressure. Many males are quickly brought to erection when pressure is applied on the perineal surface at a point which is about midway between the anus and the scrotum. In the case of the female, strong pressure applied from inside on the posterior (lower) wall at the back of the vagina may stimulate these same nerves, and this is one of the sources of the satisfaction which many females experience when the vagina is penetrated in coitus. Deep penetrations of the rectum may stimulate the same perineal nerves, and prove to be similarly erotic.

Thighs
The thin-skinned, inner surfaces of the thighs, particularly on their midlines, are richly supplied with nerves. Any tactile stimulation of these areas may contribute to erotic arousal. Such stimulation may bring responses of the adductor muscles on the inner faces of the thighs, and of the abductor muscles which are located on the outer surfaces of the legs, and as a result the thighs may be rolled together or thrown apart with distinctive movements that are characteristic of much coital, masturbatory, and other sexual activity. These movements of the adductors and abductors are also involved in the build-up of nervous tensions throughout the whole body.
There are abundant data in our records on the erotic sensitivity of the inner surfaces of the thigh. There are few references in the published studies, but see: Van de Velde 1930:45. Havelock Ellis 1936(11,2):113. Kahn 1939:70. Fulton 1949:140 records that manipulation of this area can cause penile erection in dogs, cats, monkeys, and humans whose spinal cords are severed.

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