It's safe to say that by now, most of us know a thing or two about sex — but though we've gained plenty of experience through the years, the primal act still seems like a mystery. Yes, we spend a ton of time reading, watching and practicing intercourse, but no matter how long we've been doing it, it always seems like there's more to learn.

Case in point? These crazy facts. From the reason we don't pee all over ourselves mid-thrust to the skinny on why food is a turn-on, you're gonna wanna check these puppies out.

Vibrators were invented for something else
The vibrator was originally invented in the 19th century as a way to reduce "hysteria." That seems a little extreme. However, we do not recommend testing that theory by taking away a woman's vibrator to see if she goes into a hysterical fit. That's just dangerous.

The sperm ratio
Your average healthy man produces approximately 300 million sperm in just a teaspoon of his semen. However, it only takes one little swimmer to fertilize a woman’s egg and it can live for up to a week inside your body.

More: 6 Positions That Make Anal Sex Easier & Less Intimidating

The first thing people do after sex is...
Forget post-coital cuddling! According to a poll by consumer electronics site Retrevo.com, 36 percent of people under the age of 35 check their Facebook and Twitter accounts after a roll in the hay. Hopefully, they are not posting any pictures!

Which sex actually gets busy more often
Think men get laid more than women? Wrong! According to Men’s Fitness, women have sex 17 percent more often than the average guy. Go girls!

The longest orgasm
Even though the male O seems to get all the attention, it turns out the women get the last laugh when it comes to climaxing. The average female orgasm lasts 20 seconds — 14 seconds longer than the male's six-second O.

Orgasms are good for you
Orgasms are good for your health! They can lower a woman's risk of heart disease, stroke, breast cancer and even depression. So have sex and get happy!

Sexercise is not a myth
Sex counts as a workout! During 30 minutes of active sex, you burn about 200 calories. And you can even have an orgasm while working out.

Women are friskier than we admit
Even though straight women reported only being aroused by men, researchers at the Queen's University in Kingston, Ontario, found that most women in a study became aroused by every sexual stimulus they saw — including nude male and female bodies, heterosexual and homosexual sex and even animal sex.

Sex makes you dirty, in a good way
When aroused, people are not as likely to think things are disgusting, according to a study published in the online journal PLOS ONE.

How your brain responds to sex
Researchers at Rutgers University, who used fMRI scanners to find out exactly what happens in your brain when you're aroused, found that different regions of the brain became activated in response to stimulation of the vagina, cervix, clitoris and nipples.