The director of Jessica Alba's latest film shows how a sex scene is really made.

How do you film a sex scene?

It’s not a question one often asks themselves but if you guessed: place two actors on a bed, squirt them with some fake sweat and direct a lot of vigorous shoulder jerking, you’re pretty close.

Behind-the-scenes footage from Joe Carnahan’s action film Stretch (which starred Jessica Alba, Chris Pine and Ed Helms) has given audiences an inside look at how utterly unromantic the joining of two can be.

The clip which stars Brooklyn Decker and Patrick Wilson presents the event as a co-ordinated collaboration of tacky background tunes, awkward laughter and one valiant cry of 'action!'.

In terms of content and shooting style, the scene is relatively tame - especially compared to such contemporaries as what is shown during Lena Dunham's tv series Girls.

Dunham has been very open about the ins and outs of her scenes, openly admitting during a group interview with other female comedians that she doesn't use genital patches .

"I stopped wearing the nude patch after the first season of Girls. There’s not one guy who works on that show who hasn’t seen the inside of my vagina…This patch – you glue it over your vagina. It gets sweaty and always falls off." Dunham said.

There are no vagina patches in Stretch but there is a lot of adjusting

Adjusting, apologies and shots of bare shoulders.

Here's the scene that reveals it all...

"Sorry." says Wilson, twisting his body to speak to the director whilst still lying atop her.

"Oh - no, you're good." says Decker.

The two share a belly laugh with director until the scene begins and suddenly, both are thrust into full-tilt action.

When the scene climaxes, the crew starts to laugh and the runner rushes to re-apply the fake sweat.

"Is that enough f*cking? Wilson asks.

"That was a lot of f*cking! Great f*cking, good job!" Carnahan said.

The scene may not be oozing with Barry White levels of sex appeal but it does offer a raw glimpse at what happens behind the curtain.

Watch as the MM team share just how much Barry White gets played at our homes.