The Refractory Period: The Real Reason Guys Need a Break Between Orgasms.

Of course, none of us have had this problem before.  It's always the other guy.  What does happen when he can't go again?  Is it really his fault?  Too much to drink? Does he just not want to do "it" with you again?  Once was enough?  Maybe it is one of those reasons, but most likely, no matter how horny you both are, sometimes you can't beat science. 

Thanks to Greatist.com, we have a pretty scientific explanation below.

We've all been there: After one inning between the sheets, not everyone’s ready for round two. Women may be primed to go seconds after the first big win, but for men, it’s not so easy. No matter what his brain is saying, his body just won’t comply. What gives?

Guys actually have a built-in recovery period (nature's cockblock, if you will) after sex. It’s called the male refractory period (MRP), and it’s the time after ejaculation—lasting anywhere from a few minutes to a few days—where a guy is unable to get an erection again. While women don’t have an equivalent (allowing for the possibility of multiple orgasms—lucky them), every man experiences some kind of post-ejaculation recovery period.

The Science Behind the Big O

After ejaculation, your whole body is on overdrive. And your sympathetic nervous system—which controls the fight-or-flight response—pushes for your body to calm down, explains Charles Walker, M.D., assistant professor of urology and cofounder of the Cardiovascular and Sexual Health Clinic at Yale University. This activates the release of neurotransmitters, which cause the smooth muscle in the penis to contract, driving a guy into a flaccid fix.

What happens next is a domino effect, lowering levels of neurotransmitters, namely dopamine and testosterone. Dopamine, one of your “happiness” hormones, is secreted when you're aroused. But when your system wants you to come off that high, it dampens production of it. In fact, one study found that the more of your dopamine receptors that are blocked, the longer the refractory period lasts.

At the same time, production of serotonin and prolactin is increased, which also counteracts arousal. Prolactin is the hormone most strongly associated with the refractory period—the lower your prolactin levels, the quicker you can get going again. One study found that for men who report being able to have multiple orgasms, their bodies release no prolactin post-climax. (Note: Ejaculation and orgasm aren't the same thing—they're two separate processes. If a man can refrain from ejaculating during orgasm, he may be able to have multiple orgasms. It's a rare phenomenon because it takes practice to be proficient.)

Prolactin also explains why the MRP lasts longer when you orgasm from actual sex versus self-pleasure. The amount of prolactin released after intercourse is 400 percent greater than following masturbation, research says. And while that sounds like a bummer, researchers point out that this means sex is more physiologically satisfying than masturbation.

Another side effect of increased prolactin: the suppression of the production of testosterone, a key player in piquing your interest in sex. Also after the big O, your brain releases a surge of serotonin, which makes guys want to just roll over and sleep after sex. (So that explains it.) One study of post-coitus brain scans revealed that ejaculation causes less activity in the prefrontal cortex and a release of oxytocin and serotonin, shutting off alertness and mental activity and essentially kneecapping any sexual desire.

So not only are your hormones working to actively make you not aroused, but you also have less of the hormones that are responsible for getting your engines running. But don’t worry—it’s not as hopeless as it sounds.

OK, How Long Will It Last?

It depends on a handful of factors, experts say. The biggest? Age. “Teenage boys can have a refractory period of a few minutes, a 30-year-old man is typically unable to have a second orgasm for half an hour or more, and for many men 50 years and older, one orgasm per day may be all they can achieve,” says Abraham Morgentaler, M.D., associate clinical professor of urology at Harvard Medical School and author of The Truth About Men and Sex: Intimate Stories from the Doctor’s Office.

Other factors that come into play: level of desire, level of sensitivity, how turned on you are, the quality and emotional state of your relationship, whether you’ve been drinking, whether you’re circumcised, what medications you’re on, how comfortable you are in your environment—pretty much everything that would affect your ability to get it up to start with, but even more so because you’re fighting against your body’s natural inclinations to recharge.

Every guy is wired differently too. “A young man may be able to have five or more erections and orgasms in a day with a new partner, whereas another young man in the same circumstances may not have the urge or ability to have more than one,” Morgentaler adds.

Get Back in the Game Faster

For most people, this forced break isn’t a huge problem. The biggest issue is if it’s affecting a partner's pleasure after he finishes first. It can also be an inconvenience for younger couples who want to have back-to-back romping sessions. (Note: For some guys, they can still have an erection, but no orgasm, during the MRP, Morgentaler adds.)

How can you minimize the wait time? You can’t really control (or predict) it. But there's one thing both docs agree helps speed up your time between innings: increasing arousal. “In especially exciting circumstances, all bets are off, and men may surprise themselves with how quickly their erection returns and their ability to have orgasms in relatively rapid succession,” Morgentaler says. (Some ideas to spice things up: Rent a hotel room instead of having sex at home, have morning sex instead of at night, or buy some lingerie—even small efforts to add novelty may be enough for excitement overpower your systems, Morgentaler adds.)

And remember: “You don’t need an erection to give and receive pleasure,” says Jessica O’Reilly, Ph.D., a sexologist and Greatist expert. ”You’ve got ten good fingers, a tongue, and hopefully some toys that can help [your partner] reach climax during the MRP.”

The Takeaway

For the most part, the refractory period is a natural phenomenon and is your body’s way of healing and protecting your crown jewels. If you’re young and healthy but spending hours on the sidelines, ask your doc. It could be a side effect of medications (antidepressants in particular mess with your dopamine and serotonin levels), Walker says. And there are other prescriptions that can help your hard-on bounce back faster, like Viagra, although not necessarily your ability to orgasm again.  – greatist.com

So now, if it comes to it that you don't want to ever do round two with him, you can sound all scientific-y when you say, " I also have a big refractory period."