It is important to remember that the phenomena we are here concerned with are essentially normal.  Many of them are commonly spoken of as perversions.  In so far, however, as they are aids to tumescence they must be regarded as coming within the range of normal variation.  They may be considered unaesthetic, but that is another matter.  It has, moreover, to be remembered that aesthetic values are changed under the influence of sexual emotion; from the lover’s point of view many things are beautiful which are unbeautiful from the point of view of him who is not a lover, and the greater the degree to which the lover is swayed by his passion the greater the extent to which his normal aesthetic standard is liable to be modified.  A broad consideration of the phenomena among civilized and uncivilized peoples amply suffices to show the fallacy of the tendency, so common among unscientific writers on these subjects, to introduce normal aesthetic standards into the sexual sphere.  From the normal standpoint of ordinary daily life, indeed, the whole process of sex is unaesthetic, except the earlier stages of tumescence.[17]

So long as they constitute a part of the phase of tumescence, the utilization of the sexual excitations obtainable through these channels must be considered within the normal range of variation, as we may observe, indeed, among many animals.  When, however, such contacts of the orifices of the body, other than those of the male and female sexual organs proper, are used to procure not merely tumescence, but detumescence, they become, in the strict and technical sense, perversions.  They are perversions in exactly the same sense as are the methods of intercourse which involve the use of checks to prevent fecundation.  The aesthetic question, however, remains the same as if we were dealing with tumescence.  It is necessary that this should be pointed out clearly, even at the risk of misapprehension, as confusions are here very common.

The essentially sexual character of the sensitivity of the orificial contacts is shown by the fact that it may sometimes be accidentally developed even in early childhood.  This is well illustrated in a case recorded by Fere.  A little girl of 4, of nervous temperament and liable to fits of anger in which she would roll on the ground and tear her clothes, once ran out into the garden in such a fit of temper and threw herself on the lawn in a half-naked condition.  As she lay there two dogs with whom she was accustomed to play came up and began to lick the uncovered parts of the body.  It so happened that as one dog licked her mouth the other licked her sexual parts.  She experienced a shock of intense sensation which she could never forget and never describe, accompanied by a delicious tension of the sexual organs.  She rose and ran away with a feeling of shame, though she could not comprehend what had happened.  The impression thus made was so profound that it persisted throughout life and