Can we have a serious talk about kissing? Have you ever noticed in old movies when Bogart or Clark Gable kissed a girl, her head would go back and his head would push forward? It wasn’t just a kiss, it was a symbolic act of invasion, a D-Day landing by the forces of masculinity. Indeed, an act of penetration by him, and submission from her.

That’s how the movie kiss was in the ‘30s, even after the Hays Code tried to stamp out all lust and licentiousness in American cinema, including within marriage. (You may find this strange, kids, but married couples had to have separate single beds in movies under the Hays Code).

The problem for the censors was that kissing is resilient. The lips fought back in films like Gone with the Wind (1939), where Rhett (Gable) told Scarlett (Vivien Leigh) she needed kissing badly and often, "and by someone who knows how".  He kissed her often, if not badly. Gable was the star kisser of that era. His kisses were an event. Whoosh! He’d take a fast-bowler’s run up from several metres away, grab the gal with both arms, bend her back and line up his moustache for landing just below the nose. Smack! Sometimes he’d pick her up and cradle her in his arms and then kiss her so there was no getting away. A girl knew she’d been kissed when Gable did the job – and not just kissed, but boarded, like a train!

I suspect movie kisses of the modern era are much less powerful than they were when sex was hard to depict on screen. The Hays Code made kissing more exciting, rather than less. A kiss stood for so much more: it was not just a kiss. There are of course some great modern kissers in movies (step forward Emma Stone) but the kisses don’t work as substitutes now. They’re more like Act One, followed by a striptease as the kissers get to work on Act Two. Kiss, peel, kiss, peel.

When censorship was still a major force, the kissed woman would often reel backwards away from camera, so that we did not see lip against lip. This was Hollywood’s way of getting away with it. Those standards were broken in the 1950s, by a series of movies that did not seek to hide the kiss. When the waves crashed in on Deborah Kerr kissing Burt Lancaster in From Here to Eternity (1953), she was on top, kissing him. That was fairly new. In most movies, then and now, the woman is below the man, looking up, when she’s kissed. Tall girls rarely get kissed by short men in movies, unless it’s for laughs. Deborah Kerr broke off the kiss, ran up the Hawaiian beach and flopped down on her towel, as Burt followed. He stands in mid-shot above her, magnificent chest heaving, then dives in for a kiss that might have stirred Mount Kilauea into eruption. "I never knew it could be like this," she says, breathlessly. "Nobody ever kissed me the way you do…" You said it, sister.

Even so, no one in movies in that era kissed with an open mouth. That bridge was not crossed till 1961, when Warren Beatty and Natalie Wood established the new frontier, in Splendour in the Grass. Saliva was exchanged. Will Hays died the next year, probably from shock, but in that moment, movies grew up, at least a little.

The modern girl doesn’t always take a lower position now, and she controls how and when it happens. Lauren Bacall established that in 1946 in To Have and Have Not when she sat on Bogart’s knee and kissed him. He was surprised, taken aback. "Whadya do that for?" he asks. "I’ve been wondering whether I’d like it," she responds. Then she kisses him again: all her choice. He’s now the one whose head is pushed back. He’s now the train.

So the position is a key point in movie kissing. In Titanic, one of the great modern-era kisses takes place at the front of the ship, when Kate Winslet bends her head back and to the right to kiss Leo DiCaprio. The line of her neck, with her arms holding the guy wires, makes this kiss supremely erotic – much more than if she had been facing him. In Spider-Man (2002), Tobey Maguire, in his superhero suit, hangs upside down in front of Kirsten Dunst, in the rain. She peels off the bottom part of his mask and kisses his lips, in one of the most iconic kisses of the modern era. Why is it sexy? Because it changes the power dynamic. Mr Superhero is not in control of the kiss. Again, the woman decides.

Gable must wonder where all these sissy guys came from, but he’d be wrong. Modern guys still kiss forcefully, and the fast-bowler’s run-up has not disappeared, but girls do that too now, sometimes flinging themselves into the air and wrapping their legs around the man. Movie kissing is now more a level playing field. Not entirely, because submission and swooning are still attractive to the romantically inclined viewer, but the kisses are less often stolen or taken by force. That’s a good thing, even if the kiss may have lost some of its metaphoric power. It’s not the fault of the lips that the loins have taken over.

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