The penis and clitoral/vulva/vagina/cervix, particularly their skins and sub-layers, serve as the 2ndary neuroendocrine system synthesizing neurotransmitters, sex hormones and prostaglandins, in addition to their primary link of vagal nerves to the hypothalamus-pituitary which as as the primary neuroendocrine system. The 2ndary neuro-endocrine function is driven by the pelvic autonomic nervous system - the parasympathetic nervous circuits S1-S5 and C0 from the tailbone and the sympathetic nervous circuits from the spinal cord T12 and L1 - L5. A prolonged vaginal intercourse (about 30-90 minutes) fires up the heat on the penis and vagina to promote the neuroendocrine function for health and well-being.  It is the best medicine for you. Please note that having sex longer than 90 minutes or so can use up the essential enzymes in the hormonal and neurotransmitter production, and trigger the Yin-type stressor cortisol release from the hypothalamus, adrenal medulla and local skin to initiate the sympathetic nervous Fight (ejaculation or precum flooding) or Flight (going limp) responses. The Old Chinese old Taoists (men or women) used 8 penile-vaginal mutual massages (summarized as  the screwing sex method by Dr. Lin) without ejaculation to benefit health and cure male and female sexual disorders.  The theory of Dr. Lin's Screwing Sex is based upon the fact that the skin and its sublayers under chemical or mechanical stimulation serve as a 2ndary euroendocrine system supplementing the main hypothalamus-pituitary-adrenal, - testicular and thyroidal axis. All you need is to have a prolonging penle-vaginal mutual massage without ejaculation or abrasion.

Simple Rule: Constant and frequent intercourse can prevent shrinkage of your sex organs, but frequent orgasm and ejaculation can exhaust your brain and hypothalamus-testicular (ovarian) axis unless you can stop norepinephrine-epinephrine conversion and supply your brain enough acetylcholine/serotonin/GABA.
Orgasm News:
1. Semen can reduce the chance of ovarian cancers if it contains less prostaglandin E2 and more prostaglandin E1. South Korea researchers shows the semen extract can kill ovarian cancer cells (updated on10/27/2003); Semen's androgen hormones and prostaglandins can easily absorbed by the vaginal/cervical/uterine membrane and receptors to produce androgen hormone replacement therapy- resulting in anti-depression and to stimulate the ovarian function for progesterone production which can eventually be turned into testosterone and estrogen.
2. Yale's report "A History of Frequent Orgasm or Tampon Use During Menses Protects Against Endometriosis"
==> http://info.med.yale.edu/obgyn/kliman/Endometriosis/EndomAbstracts/Orgasm.html  
3. Orgasm triggers the pituitary to release prolactin - then 16K-prolactin. Although chronically excessive prolactin can disable the sexual function, induce cancerous development, screw up the reproduction system and cause depression, an optimal prolactin release from your pituitary and eyes, as a result of an orgasm, is good for hGH production, cancer and tumor prevention and for healthy eyes, brain, heart, liver, kidneys, uterus and prostate. Particularly, if chondrocytes (bone marrow stromal stem cells) can release the enzyme matrix metalloproteinases to convert prolactin into 16K-prolactin (16 kDa N-terminal fragment of the hormone prolactin), you will benefit from the antiangiogenic effects from 16K-prolactin. 16K-prolactin can block the blood vessel invasion or new blood vessel growth, associated with the endochondral bone formation (blocking mitogen-induced vascular endothelial cell proliferation, involved activation of programmed cell death) and tissue repair after injury and inflammation (by prostaglandin E2!),  which is an important mechanism underlying human diseases such as cancer, diabetic retinopathy, rheumatoid arthritis, and heart diseases. It is antiangiogenic, but excessive 16K-prolactin inhibits the penile or clitoral growth, or other normal cellular or nervous repair and regeneration/rejuvenation.  Therefore, you need an optimal orgasm frequency to prevent cancers (including prostate cancers), tumors and retinopathy (non-inflammatory damage to the retina of the eye, due to lack of of the blood supply, damaged or constricted blood vessels.)  However, you should not have an excessive sex or orgasm since it will produce excessive stress hormones to inhibit the release of the enzyme matrix metalloproteinases, to suppress the neuro-immune system,  and to activate the inflammatory factors triggering your health alarm system, as a result of the excessive prostaglandin E2 production. The inflammatory factors actually damage the bone marrow cells. Due to the fact that semen contains high concentration of Phosphorylcholine essential to the brain and nervous function and repair, the old Taoists theorized that men can return semen (actually phosphorylcholine) to revert the brain. Generally speaking, the concept is correct; however,  when the brain's dopamine or testosterone level is too high for excessive semen production, your pituitary will be over-exited, leading to excessive oxytocin release and prolactin deficiency, in addition to neuroexcitotocity from dopamine-induced excessive glutamate and histamine production, the deamination of dopamine to DOPAL and the oxidative stress from the demination byproduct Hydrogen Peroxide.  Therefore, Optimal orgasm and ejaculation can help you burn some dopamine and testosterone out,  and then induce the prolactin release from the pituitary and retina tissues for some protective and anti-inflammatory hormone 16K-prolactin in cooling down the nervous systems. In this way, you can avoid the side effects of excessive dopamine or testosterone, and benefit from sex. That is, an optimal orgasm or sex can improve your health.
Remember this:
Bone Morrow and Sperms: Reuters (April 13, 2007) said Dr. Karim Nayernia at the University of Gottingen, discovered stem cells taken from the bone marrow of men may be able to transdifferentiate to sperm cells in 3-5 years. 
The Traditional Chinese Medicine considered bone marrow is Essence (Jing) for semen production. What is a coincidence! This means that over-ejaculation or excessive orgasm will cost your bone marrow and weaken your bone. Other stem cells researches have done similar work in female mice and turned bone marrow cells into egg cells. What does this mean to women's body pains or arthritis?  This means excessive orgasm/sex/ejaculation, job-related stress, substance abuse or toxins can inhibit the enzyme matrix metalloproteinases from the bone marrow stromal stem cells.  This is why our readers kept reporting inflammatory pains and arthritis induced by orgasm/ejaculation,  job-related stress, substance abuse or toxins. 
4. You will get another benefit from sex and orgasm if you get a resulted elevation of both GABA and glutathione which are converted from excitototoxicity glutamate. GABA is synthesized from glutamate using the enzyme L-glutamic acid decarboxylase and pyridoxal phosphate as a cofactor, and glutathione from the amino acids L-cysteine, L-glutamate and glycine in two adenosine triphosphate-dependent steps:   by combining L-glutamate and cysteine via the enzyme gamma-glutamylcysteine synthetase to form gamma-glutamylcysteine, and then adding glycine to gamma-glutamylcysteine via the enzyme glutathione synthetase to produce glutathione. Elevation of GABA with serotonin, norepinephrine and prolactin after sex or orgasm will trigger the pineal gland and retina to release melatonin for better sleeping, hGH production, nervous regrowth, neuro-endocrine restoration, cellular repair,  and shaper vision;  Elevating of glutathione can reduce the formation of  oxidative toxins, such as Hydrogen peroxide (H₂O₂),  associated with oxidative injury and cellular/nervous damage.  However, if you lack of these liver enzymes ( L-glutamic acid decarboxylase, pyridoxal phosphate , gamma-glutamylcysteine synthetase and glutathione synthetase)  and amino acids L-cysteine and glycine, you will get excitotoxicity and brain/nervous damage from your orgasm sponsoring neurotransmitters glutamate, dopamine, norepinephrine, epinephrine and histamine which stimulate the gene over-expression of monoamine oxidase in your brain, liver, kidneys, adrenal glands, heart and other organs for premature ageing, brain and nervous damage,  and sexual exhaustion symptoms (as listed in http://www.actionlove.com/cases/case9848.htm).
5. Sexual arousal, ejaculation or orgasm induces a burst of norepinephrine and epinephrine release.  For a health person, the norepinephrine and epinephrine release is supposed to stop in few minutes after sex and drops in maintaining the homeostasis. Overall, the norepinephrine and epinephrine level will stay higher for few hours.  Norepinephrine and epinephrine can trigger both proinflammatory and anti-inflammatory cytokines and kinases in the immune system via the stimulation of the alpha- and beta-adrenergic receptors.   Moderate increase in norepinephrne and epinephrine during and fater sex results in increase in the concentration of lymphocytes in the bloodstream for immune enhancemen; t and the anti-inflammatory cytokins overpowers the side effects produced by proinflammatory cyrockins.  That is why optimal sex, like moderate exercises, can improve your health and neuroimmune function. However, excessive norepinephrine induces more proinflammatory effects than anti-inflammatory ones, leading to excessive prostaglandin E2 production to set your brain and body on fire - over-heating, immune disorder and inflammatory responses. This is what you have to concern about.
6. Sex improves neuroimmune in many ways via 1). an elevation of hypothalamic and adrenal dopamine and norepinephrine release for the sympathetic nervous fight, 2). the activation of the cholinergic anti-inflammatory pathway via the vagal acetylcholine and parasympathetic (acetylcholine) tone that inhibit proinflammatory cytockines such as interleuck(IL)-6, and 3). the immune challenge in the adaptive immune function and immunological memory, as an evolution process of the immune system, for the stronger and faster immune defensive responses. Regular and normal sexual activities boost systemic immune specificity, inducibility and adaptation. However, failures of host defense can occur when the hypothalamus-pituitary-adrenal axis constantly, excessively  release norepinephrine and prolactin for inducing excessively production of the immune suppressor and inflammatory hormone prostaglandin E2 that damage or scar organs, when the cholinergic ant-inflammation pathway is overpowered by the norepinephrine and sympathetic nervous inflammatory pathway,  when immunodeficiencies occur as one or more of the components of the immune system becom inactive due to drug abuse or ageing, or when adaptive immune system is exhausted.
7. Sex promotes emotional binding, happiness and satisfaction via the release of the pituitary toning hormones arginine vasopressin (AVP), oxytocin, prolactin, hGH (Human Growth Hormone)  and endorphin via the vagal nerve stimulation in the sex organs and breasts/nipples. Thus, the sexual vagal nerves stimulation is responsible for emotional development and sex organ regrowth.  The vagal nerve contains approximately 80% of the sensory fibers to sense the physical, chemical or biological stimulation all over the internal and external organs (nipples, testicles, penis, vagina and clitoris). They convey the stimulation signal to the hypothalamus-pituitary axis for necessary responses via the vagal motoring nerves and autonomic nervous system (both parasympathetic and sympathetic). The vagal nerve in the sex organs has been recently identified and verified. Sex organ stimulation will induce the hypothalamus-pituitary axis to produce and release AVP, oxytocin, prolactin, hGH, and endorphin via the vagal sensory nerve.
Sex can stimulate the cholinergic/vagal nervous
8. Finally, you should have tightly body-contact mutual massage on the breasts/nipples, the vagina, the cervix, the penis,  and the low abdomen, particularly the pubis and the acupuncture point Dan-Tien, the middle point between the belly button (navel or  umbilicus) and clitoris can stimulate the vagal nervous system. Vagal tone plays a key role in the health and disease prevention.  Today, vagal nervous stimulation becomes a health therapy for many nervous disorders and gastroenteritis.  Thus, you can have frequent sex for health,with Dr. Lin's screwing method - http://www.actionlove.com/love/screw.htm

He said 'Since getting back in the Midnight Cowboy business, your products have been helping a lot. Thank you.....Last week I serviced 10 clients in one day' How to benefit your body from serving 10 clients a day - the Old Taoism theory: extract the female essence via sexual intercourse and female orgasm br>http://www.actionlove.com/cases/case16743.htm
She said 'I have been taking your medicines now for well over a month, and have found some really encouraging results!' with ViaPal-hGH-P and ArgiNOx for withdrawal of SSRIs antidepressants and restoration of sexual orgasm.
==> http://www.actionlove.com/cases/case15311.htm
He said ' Her urinary incontinence has almost completely disappeared. Her doctor was very surprised, because his prognosis was that she may always have some degree of problem. She was able to stop taking the medication that she was on to treat this problem, which didn’t help the condition very much anyway. To sum things up, Dr . Lin, I am 100% convinced that you are correct about this. Dog sex provides an effective therapy for at least some of the underlying causes of female urinary incontinence.' for restoration of sexual orgasm with Dog Sex (Biofeedback Heat Therapy)!  On thermal and bioelectric beneficial effects of the penis and semen on the female continuous orgasm, vagina/urethral health, vaginal tightness and urinary continence
==> http://www.actionlove.com/cases/case13627.htm
Do you have a penetration pleasure for vaginal sexual orgasm ?
http://www.actionlove.com/cases/case14720.htm
A female reader's advices for more sexual orgasm - the Tao of Love.
==> http://www.actionlove.com/cases/case12127.htm
Does sexual orgasm kill or heal? Orgasm is beneficial or destructive to health?
==> http://www.actionlove.com/cases/case12926.htm
If you can not make her achieve sexual orgasm and then let her feel unfulfilled with persistent arousal and pelvic inflammation, you make love for divorce.
==> http://www.actionlove.com/cases/case14701.htm
Over-masturbation/Over-ejaculation and long-term non-orgasm semen retention are two extremes for no sexual orgasm!
==> http://www.actionlove.com/cases/case14184.htm
Chronic over-masturbating from age 14-31 results in all of the sexual exhaustion symptoms, some fatigue, graying of hair, hair thinning, eye floaters, sinus, ear aches, and sleeping disorder for no more sexual orgasm. On the arylalklamine N-acetyltransferase gene expression disorder in the pineal gland and retina for circadian rhythm and visual nervous disorders. Why can a good sex improve your health?
http://www.actionlove.com/cases/case12909.htm 
Birth control pills negatively affect her libido and sexual orgasm, but positively give  her a weight gain of about 40 pounds - why?.
==> http://www.actionlove.com/cases/case11972.htm
Female over-masturbation, ear buzzing, eye floater, losing mind concentration, and shortened menstruation for no sexual orgasm. On the benefits of lovemaking for women.
==>http://www.actionlove.com/cases/case11721.htm
Sexual dysfunction caused by Semen Retention for no sexual orgasm - How monks disable their prostate's seminal production and then disarm their penises. And how a woman has an atrophy vagina.
==> http://www.actionlove.com/cases/case11243.htm
How to enlarge your penis via lovemaking for her multiple sexual orgasms
==> http://www.actionlove.com/cases/case11201.htm
Prostaglandins E-1 and E-2 in semen can help trigger women's sexual orgasm
==> http://www.actionlove.com/cases/case10364.htm
He said 'very satisfied with your products!' - How to maximize the benefits from sex and ViaPal-hGH-P for more sexual orgasm
==> http://www.actionlove.com/cases/case9759.htm
ViaGrowth-II helps him release tight muscles and Dr. Lin's Sexual ChiKong makes him last for 90 minutes and gives her a lot of sexual orgasm
==>http://www.actionlove.com/cases/case8944.htm
He and his girl friend get extraordinary benefits from sexual orgasm with Dr. Lin's formulas.
==>http://www.actionlove.com/cases/case8949.htm
Practice Sexual ChiKong to benefit your body from sexual orgasm
==>http://www.actionlove.com/cases/case8996.htm