Labored breathing. Undulating fats dripping sweat. Pungent smells and fluids of all sorts leaking out of every orifice.
According to several recent studies, the human body is both exceptionally gross and fantastically weird, and never more so than when it is engaged in the act that makes new human bodies. Despite exceptional amounts of popular interest, the physical effects of intercourse on the body have historically proven somewhat difficult to study.
For many years, religiously-motivated concerns about morality prevented studies from happening, and even when a study finally gets underway, other problems presented themselves. "The Observer Effect" states that it is impossible to stick a bunch of electrodes on a couple, set up a bunch of recording and monitoring devices, and watch them having relations from behind a two-way mirror and yield identical results.
Despite all of those obstacles, we have managed to learn a few things about what happens to your body while having sex. Here is a list of some of the gross, weird, fun, awesome, hilarious, and confusing things that humans do when they're doin' it.
Breasts Grow During Arousal
Increased blood flow to the area can cause a woman's breasts to swell to up to 25 percent larger than in their non-aroused state, which men should file away under extra incentives to take their time before "doing the deed" (as if they didn't have enough already).
Stimulation promotes circulation in general and encourages blood flow to the "sensitive" zones (such as the chest and nipples) in particular. Women's breasts may change in color slightly, with redness or blotchiness appearing on the chest and the areolas and nipples darkening. As the nipples harden and the areolas become enlarged, the whole area becomes far more sensitive to the touch. Play your cards just right and some women can even climax from nipple stimulation alone.
Your Brain Gets You High
Let's face the facts: we're all addicts. Maybe you're not hooked on the "traditional stuff," but admit it: you're addicted to something. The body is just one big series of chemical reactions, and historically, one of humanity's favorite drugs to experiment with happens in the bedroom.
During the arousal process, the brain stem releases the pleasure chemical dopamine, your adrenal glands start producing adrenaline, and the hypothalamus secretes even more happy juice into the blood in the form of oxytocin and prolactin. Once you start reaching climax, however, the secreting stops and the full-on flooding begins. Dopamine, prolactin, and oxytocin, plus phenylethylamine, vasopressin, serotonin, and other endorphins are all released during climax, creating that blissful, euphoric feeling that keeps people coming back for more.
Your Immune System Gets a Boost from Frequent Booty
This just in: the drive to be healthy starts with a healthy and regular "bedroom routine."
According to one study, sexually active people are healthier overall and take fewer sick days than their celibate co-workers (not that that excuse would fly if your boss caught you and the hottie from accounts receivable in the coat closet enjoying a little afternoon delight).
Having regular intercourse boosts your immunoglobulin A (IgA) levels, with higher levels correlating to greater duration and satisfaction - so it's not just quantity of booty that does a body good, it's the quality, too. Intercourse also helps your body's production of lymphocytes, which are a key part of the process of fighting off infections, and it increases immunoglobulin antibody levels which help your body ward off viruses, bacteria, and other invasive microbes.
So go ahead, get down tonight - for your health.
Female Genitals Suck
You kids today with your Tinders and your cosplays and your buttstuffs sometimes forget that intercourse, at its most basic level, is a biological function for procreation. As much as you might think that you're just having a nice recreational goofaround, it's hard to tell female genitalia that, so it's going to keep doing everything in its power to increase the chances of conception.
One of the vagina's tricky little moves is that it is constantly trying to suck up any and all sperm that gets inside of it. During the early phases of the arousal process, it begins "tenting," which moves the vagina and the cervix closer together and helps create a suction that pulls sperm inward. Then, during climax, the muscular contractions that a woman experiences are, in part, the genital tract further sucking inward, radically increasing the chances of sperm retention.