Just did a quick search for more info and this is the best one so far:http://www.goaskalice.columbia.edu/2136.html
Yes, it's possible, but rare. Known by some as la petite mort, "the little death," a phrase that was sometimes used in Victorian erotic literature, sexual arousal and/or orgasm can cause some women (as well as men — but it usually applies to women) to experience a sudden, temporary loss of consciousness. While this is not the norm, there are some logical explanations as to why this can occur. As people become sexually aroused, their breath shortens and quickens. For some, their breath becomes so rapid that they hyperventilate. When this happens, the normal levels of carbon dioxide in the blood fall, which may cause dizziness, lightheadedness, or actually result in fainting. Too much alcohol can also have the same effect, and may even elevate the possibility of this reaction.
Another explanation is that the brain doesn't receive enough oxygen and other nutrients because of reduced blood flow. This happens because sexual arousal causes blood to flow from the brain to the genitals. This may produce an altered state of awareness or, some say, a true loss of consciousness. Some people intentionally deprive the brain of oxygen to heighten sexual pleasure and orgasm. This practice of auto-erotic asphyxiation — by oneself or to a partner — can result in accidental death.
Fainting after orgasm could also be a symptom of a serious health condition, such as an abnormal heart rhythm. During daily activities, people with this condition may feel fine. However, when they exert themselves during exercise or sexual activity, their heart can't maintain adequate blood pressure. When the exertion ends, their heart rate decreases, but the blood vessels from the muscles remain dilated, causing them to feel faint or pass out.
If fainting happens to someone you know, or to a partner, laying flat is usually all that is needed to recover. Raising the person's legs can increase blood flow to the brain and to the heart. Once the person comes to and feels better, slow movements towards an upright position will help her or him get on her or his feet. To be safe, it's a good idea for anyone who repeatedly has these fainting "spells" to talk with her or his health care provider.
Low blood pressure leads to fainting?
We take ecstasy, and then pass out on purpose - What's going on here?