The Scientific Reasoning Behind Our Strange Sex Practices

Let’s face it, sex is weird. And gross. And the reason you exist. And¬†the driving force¬†behind the world’s technology. And you love it, don’t you, you filthy, filthy pervert?

Human beings have developed some¬†very strange sex habits, and it’s easy to look at something like, say,¬†nasolingusts¬†(nose lickers)¬†and¬†wonder, simply: why? But the science behind is actually fascinating.

The oft-repeated¬†“Rule 34” states that for every action there is an equal and opposite porn version of that somewhere on the Internet. If that’s so, then Rule 35 states that for every sexual quirk and preference, there is also a team of scientists studying that exact quirk on lab rats and college students.

We’ve come a long way since the days of¬†Alfred Kinsey¬†and this article¬†looks at all the best guesses about what’s happening down there¬†from today’s¬†top biologists, psychologists,¬†sociologists, and dominatrixes.¬†After examining the science of sex, it turns out our sex practices may not be so strange after all;¬†there’s generally¬†a very reasonable scientific rationale behind why you like what you like.¬†Not that you’re not still a disgusting¬†monster, just that¬†you’ve probably got company

 

We Kiss to Ensure Our Mates Are Capable of Raising Children

According to¬†Smithsonian¬†philematologists¬†(scientists who study kissing), when we kiss, we exchange 9 milliliters of water, 0.7 milligrams of protein,¬†0.71 mg of fats… and somewhere between¬†10 million to 1 billion bacteria. So why do it? Why expose yourself to the risks of orifice-to-orifice contact, which include¬†disease, infection,¬†beard burn,¬†and tasting someone’s bad breath?

Well… science is still working on that one. One of the confounding things is that¬†kissing is not a universal human trait¬†– it’s a relatively novel practice, evolutionarily speaking,¬†and there are plenty of cultures that do not engage in¬†romantic or sexual kissing. This¬†suggests¬†that it is more of a learned behavior than anything hardwired into our circuitry. The¬†most likely explanation¬†seems to be that kissing is a strategy for testing a potential mate’s genetic code.

Women particularly favor kissing, and especially during the early stages of a relationship, with the thought being that if a partner tastes bad to you it’s less about what they had for lunch and more about searching for¬†signs of disease, genetic imperfections, and detecting¬†little guys called¬†major¬†histocompatibility¬†complex¬†genes.

Humans are capable of tasting and even smelling MHC genes, which can indicate¬†just the right¬†amount of biodiversity¬†in order to optimize¬†your chances at having a healthy baby.¬†So maybe¬†Betty Everett¬†was more¬†right than she knew when she told your grandma¬†“it’s in his kiss.”

A Fixation on Breasts Is Indicative of a Desire to Find a Reproductively Viable Mate

To say that men have historically displayed an interest in breasts is perhaps a historical display of understatement. The question, however, is “Why?” Why do these seemingly innocuous deposits of fat above a woman’s pectoral muscles hold such a sway over so many men?

The prevailing theory is that breasts are a good indicator of female fertility and reproductive health. They are a signpost literally sticking out at members of the opposite sex, drawing attention to the fact that the bearer of said boobs is of a sexually viable age, that she is nutritionally advantaged, and perhaps even suggesting what part of her reproductive cycle she may be in.

Another theory¬†is that fetishizing breasts is just¬†another case of partialism (a fetish that applies only to a specific body part). We associate breastfeeding with pleasure at an early age, and that¬†flood of feel-good chemicals becomes associated with that otherwise non-sexual organ. Women may also cross-associate nipple stimulation with sexual desire because¬†oxytocin¬†–¬†a neuropeptide that has been shown to increase feelings of relaxation,¬†attachment, and trust – is¬†released during both breastfeeding and¬†orgasm.

Penis Size Is Only Important in Relation to Physical Compatibility

Ladies and gentlemen, the results are in, the debate is over, and we can say conclusively that in the case of Boat Size vs. Ocean Motion, penis size totally matters. Sometimes. To some women. In short: it depends. Some women do clearly favor large anatomies. Others do not. And are we talking length or girth?

Turns out, penises are different, vaginas are different, and ’s physiological and psychological makeups are different –¬†so you’re just going to have to buckle down and figure out the combination that works for you. It’ll be a rough period of trial and error, but hopefully, you’ll be able to handle the workload. Until then, here are some helpful stats about wangs: the average penis length is¬†about 5.56 inches, the average penis girth is 4.59 inches,¬†58 percent of newborn males¬†are being circumcised (and that number is dropping),¬†and¬†here’s a list¬†of some dumb things that penises have been called.

We Like Big Butts Because They Show a Woman's Ability to Handle Pregnancy

We all know that big butts are powerful enough that they can render some men¬†incapable of lies, but just what is it about having a great big round thing in one’s face that¬†gets men so sprung? Similar to the breasts, a trunk that is optimally packed with junk¬†(aka gluteal-femoral fat)¬†can¬†be an¬†indicator of genetic health and¬†sexual maturity.¬†Studies have also shown¬†that women with a little more bass tend¬†to be more intelligent¬†and more resistant to chronic illness – no word on whether any of those studies were funded by the¬†Trainor¬†Institute for Bringing Booty Back.

Current research¬†indicates that it’s not even so much the butt itself that we are interested in but the alignment of the spine and hips. Women shift their center of mass backwards during pregnancy to compensate for the extra baggage up front,¬†and what men are really looking at is their body’s capacity to handle that shift. A woman with greater “vertebral wedging” was deemed more capable of staying healthy during¬†pregnancy, surviving multiple pregnancies, and¬†rolling in Sir-Mix-a-Lot’s Mercedes.

See what else does the trick here.

Moaning During Sex Fosters Communication

Moans, groans, and dirty talk are not merely the overwrought provenance of pornographic films;¬†they actually serve¬†multiple purposes¬†within the mating ritual. The first purpose is perhaps the most obvious: it’s about¬†communicating with your partner. Moans of pleasure are positive affirmations, and dirty talk often conveys specific messages about rate, position, and religious orientation (Faster! Right there! Oh god!).

Moans also are a form of¬†method acting,¬†helping you get¬†in the mood¬†by acting like you’re in the mood.¬†Vocalizations¬†can help women through the arousal process, reach¬†the point of¬†climax, and¬†can even extend orgasms.¬†Don’t¬†fake it,¬†though –¬†lying to your partner¬†will only perpetuate bad sex, so stay vocal and positive but always honest in the sack. Also, maybe the most important reason for sex noises is that¬†without them, sex would be super quiet, awkward, and weird.

We Stimulate the Clitoris for Pleasure Because That's Literally Why It Exists

The clitoris¬†is a wonderful¬†oddity on the human body: it is the only piece of anatomy, male or female, that exists¬†purely for the purpose of pleasure.¬†Far from the tiny button it’s traditionally described as, the clitoris is actually a deep network of over¬†8,000 nerve endings¬†(twice as many as the penis) that stretches well¬†into the pelvis and connects to another 15,000 nerves.

Like the penis, the clit also engorges during arousal and becomes highly sensitive – sometimes too much so. The clitoris can retreat into its vaginal hood as it swells, preventing direct contact which, given how sensitive the clit is, is not always a helpful thing for achieving orgasm. Shamefully, we’re still trying to catch up with clitorises¬†scientifically –¬†it wasn’t until 2009¬†that we had a full sonography of an aroused clitoris, and¬†myths about clitorises¬†and¬†clitoral orgasms¬†still abound in our society (no,¬†you’rethe¬†infantile¬†one, Dr. Freud).

Masturbation Is a Way of Practicing Self-Care

According to recent data, approximately 80 percent of Americans over the age of 14 have masturbated, with men skewing significantly higher than women and younger people skewing higher than older people Рand not just teens vs. seniors. People born more recently are engaging in masturbation more (or admitting it more on surveys) than people their age did even as recently as 20 years ago. So there must be a reason so many people self-stimulate, right?

Well for men, masturbation is used in part to ensure¬†stronger, healthier sperm. The lifetime of an individual sperm is short, and masturbation clears out the backlog and allows for fresher, stronger swimmers to take the older one’s place.¬†Some evolutionary biologists¬†believe that self-stimulation¬†may have first developed in our cavemen ancestors¬†as a way to pre-game before sex so that it wouldn’t take as long, leaving one less vulnerable to attacks by¬†predators (and other males).

For ladies,¬†arousal can help their vaginas stay fresh, pH balanced, and less susceptible¬†to disease and infection. For both sexes, masturbation may be¬†an adaptation¬†to¬†help retain¬†a sense of sexual novelty while in a long-term relationship, and regular masturbation has been shown to potentially aid insomnia, improve cardiovascular health, and lower the risk of insomnia. So go ahead and have fun: doctor’s orders.

We Sleep After Sex Because It Releases Chemicals Associated with Relaxation

Men – always falling asleep after sex, right?

Well¬†yeah, kinda. There is a¬†confluence of factors¬†both biological and sociological that work together to create fodder for¬†hack¬†comedians. Perhaps the primary cause of post-orgasmic napping is the fact that with a man’s orgasm comes a flood of different chemicals including¬†prolactin,¬†vasopressin, and¬†oxytocin – all chemicals associated with relaxation and sleep. Add that to the fact that very frequently, sex is happening at the end of the day, right before bed, in bed…¬†maybe after a couple drinks…¬†plus, sex is¬†physically exhausting, so is it really any surprise that dudes have a tendency to conk right out afterward?

Fetishes Might Be the Result of Crossed Wires in Our Brains

Feet. Food. Feet covered in food… humans are into some weird stuff. A fetish¬†is¬†loosely defined¬†as any kind of sexual fixation with a non-sexual body part, substance, or object. This happens for a few reasons, one of which being that our brain isn’t always that smart and confuses easily. The parts of your brain that control your sensitive bits¬†are right next to the parts of your brain that control your feet, and¬†brain-overlap theory¬†suggests that sometimes that proximity can lead to wires getting crossed or intertwined.

This association may not even need to be necessarily¬†physical –¬†Pavlovian¬†theorists¬†assert that sexual desire can become psychologically connected to almost anything if given the right conditioning, and¬†traumatic life events¬†may somehow play a role in that association as well.

Men and Women Perform Oral Sex as a Sign of Appreciation

Similar to why we kiss, performing oral sex on a partner is a fantastic way to really get up close and personal with their genetic material at its rawest. The same MHC genes that we can detect in oral-to-oral contact we can detect in oral-to-whathaveyou contact. For women, swallowing a man’s semen is also¬†thought to be¬†a way to help her body begin to¬†recognize¬†his genetic material, making her less likely to reject it once she’s in a position to be impregnated by it¬†(and¬†for what it’s worth, after impregnation swallowing the father’s semen¬†may also help relieve morning sickness).

Men, for their part, seem to perform oral from an evolutionary standpoint as a display of skill and devotion – and out of fear of other men’s sperm.¬†Scientists have shown¬†that men that prize their partners¬†and want to keep them from straying¬†tend to perform more oral sex.

We Seek Out Aphrodisiacs to Increase Testosterone and Estrogen Production

As long as men have been insecure (so, since always) there has been a market for aphrodisiacs. From Spanish Fly to tiger penis to oysters, hundreds of products and recipes over the years have promised better erections, more (or less) stimulation, and have claimed to increase libido in both men and women. But do any of them actually work? Of course not, right?

Well, actually, while Spanish Fly is dubiously effective and the myths surrounding the magical powers of various tiger body parts have nearly led to the extinction of the species, the rumors about oysters may have some truth to them. Oysters contain two rare amino acids that have been shown to increase testosterone production in men and estrogen production in women Рso maybe that Casanova fellow was on to something. Casanova may have also correctly trumpeted the erotic virtues of cheese (he preferred stilton).

We Like Butt Stuff Because, Well, It Feels Good

In addition to the popularity of large butts, there’s also been¬†a rise in¬†butt stuff¬†in our culture in general. Pornography, advancements in hygiene¬†and the TV show¬†Girls¬†have made the rear entry less off limits than ever – for members of¬†both sexes¬†and¬†all orientations.

The anus itself is loaded with highly sensitive nerve endings, making exterior stimulation good, clean (hopefully) fun for everyone. Once inside, men and women have a slightly different layout, but both have reasons to enjoy some lovingly applied stimulation. For women, the back door can literally be a back door to the G-spot; find the right tool and the right angle and anal orgasms can be every bit as exciting as their vaginal counterparts. The male version of this is the prostate; located about two inches inside the rectum and about the size of a chestnut, the prostate can be stimulated a variety of ways that can result in orgasm Рsometimes without even touching the penis.

Drinking Makes Us More Social

It was none other than Shakespeare who¬†once wrote¬†of¬†the combination¬†of sex and alcohol that, “It provokes the desire but it takes away the performance,” and it was none other than Beyonce that¬†once sang, “I get filthy when that liquor get into me.” The sometimes symbiotic¬†relationship of¬†alcohol and¬†sex¬†is certainly a¬†complicated¬†one¬†in today’s culture, and putting aside some of the¬†pricklier implications¬†of the pairing, there is some real science behind why booze is called the “social lubricant.”

Studies show¬†that alcohol has a direct correlation to social interaction, which almost anyone will tell you is a pretty necessary¬†step in getting laid. “Beer goggles,” it turns out, are also a totally real thing. Being drunk blurs your vision,¬†decreases your standards¬†for sexual viability in a partner, and inhibits long-term decision making, which can make you more promiscuous than you would be when you’re not drunk. But once you get someone to consent to have sex with you, filthy¬†beast though you are, there is no guarantee that booze will help you during the act. Alcohol decreases sensitivity overall, and can have an especially detrimental effect in¬†one area in particular

We Watch Adult Entertainment to Become Aroused

Not to alarm¬†you, but if you’re viewing this article on the Internet¬†then¬†you are currently surrounded on all sides by pornography. For¬†better¬†or¬†worse, the Internet has exploded into ubiquity what was once considered¬†highly taboo, to the point where¬†there is¬†currently more porn¬†being made and consumed¬†than ever before in human history.

Putting aside any moral judgments about the practice,¬†the reason people like porn¬†is fairly simple (at least biologically):¬†when a person views sexually charged imagery, their mirror neurons start firing off and they get a flood of¬†dopamine¬†(pleasure chemicals). This feeling is often followed by an orgasm. Over time, this “porn =¬†pleasure” equation only gets reinforced¬†through¬†practice until there is a clear associative¬†connection between the two – but look out, it’s¬†possible¬†that¬†increased exposure can lead to desensitization and¬†addictive behavior.

Erections Are Caused By a Widening of the Blood Vessels that Carry Blood to the Penis

Hopefully, if you’re reading this, you already know that there is no bone in a boner. If you didn’t already know that, put this device down, go take a seventh-grade sex education class, and then come back once you’re caught up.

Erections actually involve (get ready to get sexy) filling the spongy tissue and network of capillaries inside the penis with blood until the entire structure attains rigidity. This process can be kicked off, as most men will tell you, by literally anything Рsexy stuff works best, though. Seeing, touching, smelling, or even just thinking about arousing concepts (whatever that might mean to any given individual) kick-starts a chain reaction beginning with the brain releasing a giant dose of nitric oxide. Not to be confused with Nitrous Oxide (Laughing Gas), NO functions as a neurotransmitter that sends a message to increase the size of the blood vessels carrying blood to the penis and to decrease the size of the vessels that carry the blood out Рwhich explains why Viagra was discovered while testing circulatory drugs. On average, an erection will make a penis 1.6 inches longer Рbut is that really such a big deal?

Money Shots Allow Men to See Their Partner's Reaction to Their 'Work'

There’s a lot of science swirling around the Internet asking the big money question: why do men like “money shots”? Why do some men take so much pleasure from watching another man’s… job well done? Science has provided little in the way of evolutionary evidence that can account for this behavior, but psychologists and sociologists have¬†plenty of theories.

Perhaps the most¬†frequently¬†repeated¬†is the idea that the facial is an act of dominance; the territorial male claiming the submissive female,¬†and indeed, facials are one of the least-searched porn categories for female viewers.¬†However, facials have also risen in prominence in direct correlation with the specter of¬†AIDS and the growth of the safe sex culture, possibly signaling a change in prevailing attitudes about the “right way to come,” with external male orgasms becoming the new normal.¬†The facial may just be a practical cinematographer’s way to get both the money shot and the partner’s reaction to it.

One explanation¬†called “erotical illusion theory”¬†actually backs that up,¬†positing¬†that the act of issuing upon a woman’s face is a “novel recombination” of classic sexual cues, specifically the moment of ejaculation combined with the facial expression¬†of their partner. Men want to be able to see their handiwork, so to speak, and they also¬†want to see their partner’s reaction to it.