What you didn't know about what happens to your vagina when you sleep.

Welcome. Did you know turtles can breathe through their butts?

Ok, ok. I know you did not click on this article to learn about the anatomy of a turtle. But the point is, this was one of my favourite facts of all time.

I never thought anything could top it.

That is until last week, in my internet travels, I stumbled upon a morsel of information that swiftly pinched the crown. Because not only is it one of those too-good-not-to-share factoids, but it also made me realise just how shamefully little I really know about my own body.

So I’m here to tell you: ladies, we have our very own version of morning wood. And it’s happening not just a little, but a lot.

The scientific term is ‘nocturnal clitoral tumescence’ (in men, it is called ‘nocturnal penile tumescence’) but the good people of Reddit came up with a far better nickname which I’ll use for simplicity’s sake: morning bean.

While the internet is awash with articles about the blokes’ morning glory, there is very, very little on the phenomenon in women. A search of ‘nocturnal clitoral tumescence’ on Google delivers 23,600 results, compared to 773,000 combined for ‘morning wood’ and ‘nocturnal penile tumescence’.

And yet it happens to the vagina-owners walking among us just as regularly. Spread the word: this gentlemen’s club is finito.

I spoke with Dr Sergio Diez Alvarez – Director of Medicine at Maitland and Kurri Kurri Hospitals, University of Newcastle – to shed a little more light on what exactly is happening down there.

First things first, the penis and the clitoris have the same embryonic origin, meaning they are different organs developed from the exact same structure. So, yes, the size difference is a dead giveaway, but they both have the same erectile tissue that responds to hormonal changes.

Let’s get scientific for a moment. When we sleep, we go through several cycles of Rapid Eye Movement (REM) sleep. This is the phase in which we dream. Diez Alvarez explains for that to take effect, there is a shift in our hormone balance because our brain has to quell our active functions for restful ones (e.g. our adrenaline levels, which suppresses erections, are reduced).

It’s this hormonal shuffle that leads to increased blood flow to your groin and – hey presto! – you have an erection. It works the same way for both the penis and the clitoris.

And nope, you don’t need to be awake. Diez Alvarez says people usually go through 4-5 REM stages per night – meaning you could be having as many as 4-5 spontaneous erections while you’re off in dreamland.

Now, we get to the fun part. You’ve probably had several sex dreams in your lifetime, or simply woken up feeling… aroused.

While men sometimes have wet dreams (or ‘nocturnal emissions’), Diez Alvarez says they typically only get the purely physical response during REM sleep. Women, however, have a physiological response. The clitoral erection is often paired with an orgasm.

“The interesting thing that’s different to males is women are more likely to have an orgasm at the same time during the dream phase,” Diez Alvarez says.

Diez Alvarez says the level of blood supply to the vagina when women are sleeping goes up significantly – as high as it does during sexual intercourse. As pulses of blood flow into the vagina, the clitoris engorges, vaginal sensitivity increases and, to put it bluntly, you become moist and warm. In other words, you’ve got yourself a recipe for the big O.

While it is difficult to measure, Diez Alvarez says women can orgasm as much as 10-30 per cent of the time during these episodes. Sometimes you’ll remember it, but usually not.

However, Diez Alvarez says you can wake up during or after REM sleep with a real sensation of a sexual erotic experience. (This is despite there being “no correlation” between this form of sexual stimulation and the usual – ahem, awake – erotic stimulation as it’s purely based on hormones.)

Of course, most women don’t realise they are experiencing a clitoral erection during and after sleep because it is so much smaller than the penile one.

But if you’ve ever wondered why you sometimes wake up feeling aroused and wet, this explains it. And you might have just had an orgasm in your sleep.

Diez Alvarez says little is known about our ‘morning bean’ compared to the men’s version. It might be because in women it is more subtle, but it also could be because male sexuality has traditionally been more acceptable to talk about. Diez Alvarez says more research and awareness would be valuable. And we wholeheartedly agree.

It can be confusing for women, and the more we understand our bodies, the more reassuring it is that what we’re experiencing on a day-to-day basis is completely healthy and normal. It’s just your morning bean saying hello.

So there you have it. Anyone else excited to go to sleep tonight?

READ MORE: There are five types of vaginas. Which one are you?