Women aren’t a mystery exactly. They’re not draped in a cloak of indecipherable secrets. It’s just that compared to guys, they’re a lot more complex. They do things like wear a waist trainer, obsess over makeup, and all sorts of other things.

Sigmund Freud, the father of modern psychology, once said women’s sexuality is the dark continent: an unchartered neverland hidden behind the folds of flesh and muscle. Although things have changed since the 19^th Century, the old riddle hasn’t changed so much, and women still remain a mystery for many men.

I did some research to unveil some of the finer sex’s more cryptic secrets. Here’s what I found:

Sexual Arousal

It’s not easy to tell if a woman is into you or not. High school sex-ed didn’t help and has undoubtedly left you with a brain full of half-truths and regrettable memories. Some of the physiological changes are noticeable, and other’s are not:

• Nipples become hard.
• Increased heart rate and blood pressure.
• Body becomes warmer and flush.
• Vagina produces lubrication.
• Erection of the clitoris.
• Elevation of the cervix and uterus.
• Expansion of the back of the vagina.
• Labia majora and minora swell with blood, increasing in size and becoming darker.

Chemical Lust

Have you ever felt uncontrollably attracted to a woman? In the animal kingdom, species use sex pheromones to indicate they’re available for breeding and attract mates. Modern chemistry has isolated two chemicals, one a by-product of testosterone produced in male sweat, and the other a derivative of estrogen in women’s urine. Dr. Ivanka Savic led a study that found female urine activates the standard scent processing part of the female brain, but triggers the hypothalamus region in men. In turn, male sweat doesn’t do anything for most other men, but produces a chemical reaction in women that results in sexual attraction.

Female Orgasm

About 26 definitions of an orgasm were listed in the journal Clinical Psychology Review, and debate continues whether or not there’s a difference between a g-spot, clitoral, and anal orgasm. Scientifically, however, it’s generally accepted that regardless of what part of her body you’re stimulating, she reacts with the same sensations:

• Involuntary muscular contractions (usually 3-15 contractions in her uterus, vagina, anus, and pelvis)
• Heart rate and blood pressure increase.
• Brain briefly goes into a trance-like state.
• Tension is quickly released upon orgasm.

Female Ejaculate

Some say it’s simply urine, some say it’s something else, and most say who cares it’s awesome. For years, the standard explanation was its urine that is secreted during an orgasm’s intense muscle contractions. Some, who have experienced it or tasted it, beg to differ. The experts all butt heads on this one, but multiple studies have shown that female ejaculate contain elevated levels of two proteins, prostate-specific acid phosphatase (PSAP) and prostate-specific antigen (PSA), both of which are also found in male semen and originate in the prostate gland-something to which women aren’t supposed to have.

Period Sex

Just because she has her period, doesn’t mean her vagina isn’t user friendly. Scientifically, there is no reason not to have sex during her period. If you have white sheets on the other hand, you may need to think through some other options: in the shower, anal, or a diaphragm. During a woman’s period her libido is heightened, and the uterine lining swells with blood, which stimulates nerve endings. Many women say sex feels better when they are menstruating. Also, orgasms release endorphins, which help with symptoms of PMS, like cramps and moodiness.

Scientific Love

Love is more than just dinner and a movie followed by hot sex. Helen Fisher from Rutgers University, New Jersey, examined the scientific forces behind love. Using “functional magnetic resonance imaging” or fMRI, she was able to peek into the brains of people that are in love. Strangely, when looking at a picture of a loved one, the region of the brain that controls emotions didn’t respond. Instead, the circuitry went deeper into the caudate nucleus, which is part of the subconscious core that houses a dense spread of receptors for a neurotransmitter called dopamine. It’s the same region of the brain that keeps gamblers up all night and cocaine addicts taking it up the nose.