A recent visit to Manhattan's legendary Museum of Sex yielded more than a mob of 18 year-old girls giggling in the foyer -- it provided an entertaining and education look into the history of sex.

Here are some little-known sex facts that may surprise you – or at least give you ammunition for a fascinating dinner conversation!

1. The best medicine...

According to the Museum of Sex, the vibrator was originally used as a medicinal treatment for female "hysteria" during the 19th century. The vibrator-induced orgasms helped doctors dissipate hysteria's anxiety-related symptoms.

2. Say cheese!

Semen contains zinc and calcium, both of which are proven to prevent tooth decay.

3. Hop to it.

The iconic "Rabbit" is renowned for two things: excellent results and an odd smiley face on its tip. Women's Health tells us the smiley face was actually a result of conservative Japanese customs. Apparently, Japanese consumers frown upon "the production of sex toys that too closely resemble phalluses," so the smiley face was added.

4. Does he measure up?

The average size of an erect penis is 5 inches, and the average flaccid penis measures about 3 inches.

5. The sad truth.

While this fact is neither entertaining nor humorous, it’s shocking to note that homosexuality remained on the American Psychiatric Association's list of mental illnesses until 1973.

6. Protect our troops.

Today the government issues "Support our Troops" paraphernalia; however government-issued brochures and videos featured a slightly different slogan during the WWII era  – "Don't forget – Put it on before you put it in."  During the Second World War, many soldiers returned home with venereal diseases, costing the government millions of dollars in medical expenses.

7. Work it.

Hate the gym? You burn about 200 calories during 30 minutes of active sex.

8. What a tease!

Burlesque costumes are the epitome of sexy – think Dita Von Teese and lingerie; however, a few centuries ago, the outfits had a slightly different purpose. According to the Museum of Sex, merkins (the bottom half of burlesque costumes) were originally created as "pubic wigs" for 15th century prostitutes. The designs helped hide pubic lice and syphilis symptoms. Make sure to share this information with your boyfriend the next time he heads to Vegas with the boys.

9. Justice is served.

In Hong Kong, adulterous husbands get more than a steep monthly alimony payment – a betrayed wife is legally allowed to kill her husband if he cheats on her – but she may only do so with her bare hands.

10. Whatever happened to Southern comfort?

The sale of sex toys and vibrators is banned in Alabama and Mississippi.

Read more:

4 Ways to sweep him off his feet
6 Steps to a sexy massage
5 Things he wants you to say in bed