10 Weird Things That Happen To Your Body During Sex

From the second you get turned on to that awesome after-sex glow, your body is doing some amazing things to make sure you experience major pleasure. But we're willing to bet you're not aware of any of this as it's happening.
Well, prepare to have your mind blown by the impressive feats that happen while you're busy getting busy.
You find everything sexy: Sure, you know the basic things that get you raring to go (firemen, Ryan Gosling, any scene from Magic Mike...), but you might be turned on by a lot more than you think. Researchers from Queens University in Kingston, Ontario found that even though straight women reported only feeling aroused by men, their measures of physiological arousal (like vaginal blood flow) told a different story. Most women in the study were aroused by every sexual stimuli they saw (nude male and female bodies, heterosexual and homosexual sex, even animal sex), while men's arousal was much more predictable. The bottom line: Women have the ability to get turned on by a much broader range of situations. Lucky you!

You're not easily grossed out: There's a reason that you're less fazed by something like sweat or weird smells when you're having sex. When you're aroused, you're less likely to view gross things as being disgusting, according to a study published in the online journal PLOS One. So that explains why you're willing to put up with just-woke-up breath for the sake of morning sex.
Your brain notices every touch: There's way more going on up there than you might think. Researchers at Rutgers University used fMRI scanners to see exactly what happens in your brain when you're aroused. They found that different brain regions were activated in response to stimulation of the vagina, cervix, clitoris, and nipples. And because your mind is pretty crucial for arousal, stimulating several of these areas at once can lead to an even more explosive finish.
You get bigger where it counts: When you're aroused, your vagina literally expands to make room for your guy. The length of your vagina starts out around 3 inches which is why it might seem pretty shallow when you're just putting in a tampon but as you get aroused, your uterus is pulled up, lengthening the vaginal wall to around 5 inches or so, says Debby Herbenick, PhD, author of Because It Feels Good. And if you're with a particularly well-endowed guy, your uterus may get pushed back a bit farther, allowing for even more room.
You feel less pain: There's a reason that things like nibbling or hair pulling don't hurt as much while you're getting it on. Your pain threshold can increase significantly during arousal, according to a study published in the Journal of Sex Research. While this might make penetration more comfortable, Herbenick warns that there could be a downside: "Some people say that they've hurt themselves and didn't realize it until after sex."
Your girls go through changes: The next time you're getting busy, take a second to check out your chest. As a result of increased blood flow to the area, you'll probably notice that your nipples are erect and a little darker in color than usual. Plus, previous research shows that some women's breasts swell during arousal and can actually increase in size.
Your body starts blushing: Studies show that your facial and body temperature increases during sexual arousal, which explains why your face and chest might get a little red when you're having sex. Plus the increased blood flow and heart rate causes a "sex flush" in some people, which appears as a red or pinkish rash on your chest that goes away after arousal subsides.
Your mind chills out: If it seems like your brain turns to mush during an orgasm, you're kind of right. The amygdala, the part of the brain involved in fear and anxiety, essentially shuts down when women have an orgasm, according to a study from the University of Groningen in the Netherlands. Even the body movements you make during orgasm are totally unconscious, according to brain scans.
Your muscles have a mind of their own: During orgasm, your body experiences a period of myotonia or muscle spasms due to the activation of the vaginal muscles, according to studies by pioneering sex researchers William Masters and Virginia Johnson. This causes the muscles in your legs, arm, neck, abdomen, and face to tense up. At the same time, involuntary vaginal contractions happen at regular intervals. Researchers still aren't sure why these spasms occur and why some women don't experience them at all.
Your bladder goes on hold: When you orgasm, your body releases an antidiuretic hormone, which is why you may not be able to pee right after sex, says Herbenick. Just don't put off hitting the bathroom too long, experts advise going after sex to help prevent UTIs.