Ah..."Pleasure"--a 251 page, 1970 book on the biology, emotions, beauty and truth of pleasure by American psychiatrist Alexander Lowen, M.D., 1910- . Lowen is a former Wilhelm Reich pupil and a founder of Bioenergetic Analysis, a psychotherapy involving rejuvenation of one's body through extensive exercising. The subtitle of this work is "A Creative Approach to Life" and in it he says, "Not only does pleasure provide the motive force for the creative process, it is also the product of that process." It is, as well, interesting to note that British medical psychologist/sexologist Havelock Ellis, in his book, "On Life and Sex" (1922), stated, "...sexual pleasure, wisely used...may prove the stimulus and liberator of our...most exalted activities."
So, to the rudiments, we should know that the release of energy or current flow culminates in satisfaction from physiological tension, sending one into the subjective state of pleasure which is a polarity of feeling. This energy charge is always equivalent to the tension in any pleasurable experience. The authenticity of pleasure sustains a person in a self-possessed state without disquietude but may nevertheless create its own "cul de sac" if its means are subdued. It may, in such cases, deny immediate satisfaction, thus providing a more everlasting gratification. Pleasure must be understood not as the aim of life but as that which is concordant with any of man's virtuous activities. The pursuit of sexual pleasure is not merely something that is sought after by animals, but something all humans should crave for, being rooted in abundance and freedom of the sex act. It should never be confounded with joy or happiness, however, for the fruit of pleasure does not always bring joy, for example when this pleasure is irrational. Joy is that which accompanies any pleasurable act that is productive and free; it is, indeed, a union of many joys which combine with power to generate happiness, to create the harmonious espousing of one's inner self with the world and way of life he lives. Sexual pleasure is a good in itself in that it is usually conducive to the general health and wellbeing of an individual. Therefore pure licentious activity and not just Eros can result in sexual joy.
A proper flow of energy is required for any pleasurable sexual experience. Energy, being the power to do work that causes motion, remains constant, conserved in that it can never be explained in a mechanistic manner, but rather as an occurrence and how it is related to its motility. Because of the unification of body and mind this energy must be of a biopsychic nature due to the psychic and biological identities that are retained. But sexual excitement entails more than the engorgement of blood vessels. Thus this vegetative current is also bioelectric in that it is found in charges of positive anions and negative kations that carry the potential to different areas of higher and lower potential in the body. This process arises from the functional antithesis of the parasympathetic nervous system which is passive and the sympathetic nervous system which is active. All human behaviour is propagated by emotion, that is the tendency to feel, usually expressed in bodily innervations at the moment the organism is stimulated. This occurs after the object has been perceived, estimated, and then the emotion is evinced and acted upon. The most pleasurable of all human emotions are the sexual, whose closest neurophysiological parallel is anger. The sexual emotions never spring from any one series of operations, and therefore we feel only part of this effect. All sexual, defensive, and hunger emotions are controlled under the sovereignty of the hypothalamus; and sexual emotions originate in a parasympathetic reaction when expansion of vegetative current from the centre of the organism to the periphery takes place. Anxiety is incident if this process is reversed, as when the body fluids are retarded and the energy moves from periphery to centre and an unpleasurable sympathetic contraction occurs. Here the heart has to overcome peripheral constriction of the blood vessels which are always inhibited. Here also the bioelectric current evolves, that is the centre, the heart and abdomen, but chiefly the solar, pelvic and hypogastric plexus. This energy becomes sexual when the appropriate reaction occurs between the parasympathetic and sympathetic nervous system, where all life processes oscillate.
Peruse "Pleasure" by Alexander Lowen to ascertain the poetic psychology of pleasure, where rainbows tinkle in fields of azure warmth.