Hold on to your hats! Did you know a man’s sweat smells different when he’s sexually aroused? Or that pulling out is almost as effective as the male condom? MSNBC provides nine of the most provocative sex studies of 2009. Here are two of them:

Sex smells. A man’s sweat smells different when he’s sexually aroused — and women can tell the difference between the smell of sexual sweat and the regular stuff, according to a study in The Journal of Neuroscience.

Pulling out works. Well, most of the time. In a paper published in the June issue of Conception magazine, researchers claimed that withdrawal was “almost as effective as the male condom” when it came to pregnancy prevention (a failure rate of 18 percent, vs. the 17 percent failure rate of condoms).

Read the full story at MSN.com.