The Biomechanics of a Kiss

It’s sensory input, of course, a delicious combination of motor conditions, chemical signalling. It’s all the biomechanics working together to create physical, emotional magic. It’s everything aligning, baby, so let's break it down!

Let’s start with the muscles, shall we?

Did you know that over thirty facial muscles need to co-ordinate for you to lay one on your loved one/top crush/netflix and chill buddy (we don’t judge!)?

It’s been two years since her brain stopped telling her muscles what to do. There is rise, there is fall, and behind the chest that ups and downs, there is a heart that taps out a mechanical goodbye. Machines doing the biomechanics for her. Paler than fog, behind her eyes, just mist. We used to walk along the valley rim at sunrise looking down on the cottony quilt of cloud resting on the valley. We are gods, we’d laugh because we thought we were invincible.

On the periphery of the room, her parents wait, scratch-eyed, hollow. Her mother - a study in how she might have aged - is coming apart at the seams. Muscles working hard to keep everything from falling to the floor. A tear in her side, interior walls ripped and all the words she wanted to say on the brink of tumbling out.

And rise. And fall.

The orbicularis oris muscle that rims the mouth is the one responsible for puckering.

There’s a twitch in her father’s mouth, the muscle spasming, like there’s a tiny electrical current being pulsed through it. He’s keeping a lid on it, of course, like he always has. As polite and remote as he was the first time she brought me home. And what is it you do? with a slight tilt to the head, a small smile that might have been an illusion. He licks his lips and even over the machines, the dry-scrape of his barren mouth roars.

Rise, pause pause pause. Fall.

In French kissing, the tongue and jaw are also (very!) engaged!

It will be strange to press my lips to hers again. Odd to feel the softness of her lips bled dry. The first time I kissed her, she looked surprised. Leftovers from the party, time had slipped through our conversation as readily as the Coopers Red we were sinking and as we pushed ourselves to standing, she’d wobbled, taken my arm. Hello? she said after the kiss registered. What was that? And I’d stumbled out an apology, but before I reached the end, she’d kissed me again, tongue probing hard into my mouth, a ferocity there that belied her small, compact body and neat bobbed hair.

Great! And what else? Well, did you know that our lips are densely packed with sensory neurons? What does that mean? Well, they are around 100 times more sensitive than your fingertips are!

In those early days, we pressed hard and good, wanting to inhabit each other’s spaces. Like clay, like dough, we wanted to lose the point where one of us ended and the other one started. There was the time in the back of the theatre for that terrible play her cousin was in that drove us hard and fast into each other’s mouths. Or the night before that three week research trip when I couldn’t bear the thought of her sipping a Parisian coffee and not tasting it on her tongue.

I don’t remember when we last kissed like that. Would I have held on, breathed all the breath we needed for both of us if I had known? I’ve kissed her forehead through the jungle of wires keeping her alive countless times over the two years, though less in recent months. But our last kiss is fogged somewhere, just out of reach, like the lingering vapours of a lost dream.

When two people kiss, their nervous systems respond to pressure, texture, and temperature through the trigeminal nerve.

The ventilator sighs out a rhythm. Two. Years. Two. Years. Our relationship measured out in pairs. Together for two. Separated by this thin veil of purgatory or limbo or whatever the fuck this is for another two. A dance that’s lasted too long and not long enough.

A year after the accident, they sat me down, her parents. Said to move on. That she wouldn’t want me to give up my life for this. I breathed hard, took two steps forward onto a dating app. Deleted my profile and came back to her bedside.

What would you do? I asked her. I thought there’d be an answer, but the reply was the suck and hiss, the beeps of the machines doing all the work for her.

And let’s look at the sensory output, too! When we kiss, our brains race ahead of us, trying to get a handle on taste, scent, and touch to figure out just how attractive, or familiar or compatible we are.

We never had to try, she and I. We just were. Even when we muttered things under our breath. Even in the throws of a fight, she’d toss up a hand, say hold up! Can we kiss this one out? And usually we did.

Her lips were soft in summer, papery and cracked in the winter. A habit of nibbling flaking skin didn’t help. She’d never use a chapstick, saying, it’s always just dehydration, don’t you know? Mock indignation when I told her to drink more water. If I could remember to drink water, I would!

They’re pressed flat now and pale. Won’t give her a second chance to manage to keep them hydrated. No more red lipstick for christmas parties, no more butter-gloss in the summer.

Yes, but what does a kiss do to our limbic system?

Well, kisses activate the amygdala which is responsible for emotion, the hippocampus where your memories are stored and the ventral tegmental area and nucleus accumbens, which have pleasure and reward covered. These in turn release dopamine which floods us with the good stuff.

There’s a polite knock on the door, a nurse nods her head into the room and says quietly, we’ll be along soon. Her mother shudders, lifts her daughter’s thin fingers from the sheet. Are you sure - I start to say, but her father puts his hand on my shoulder. She didn’t stop loving you, he says and his voice splinters at the end.

My own ventricles snap open and closed. The nerve endings in my lips tingle, like pins and needles, like there’s a fizzing drink in there instead of blood and vessels and nerves endings more sensitive than fingertips. In my pocket, there’s the silent vibration of my phone, another call perhaps, another message begging me not to cheat on her with my ex.

They say that the kisses in new relationships flood the kissers with dopamine. That this rush promotes attraction, motivation to proceed. The first kiss I had with my girlfriend of three months wasn’t like that, not at all. It was heavy, laden with all the words she’d kissed away from my mouth. I can bring sympathy, it said. I can pepper your face with understanding. But last night after the phone call with these broken parents, she said it’s being unfaithful, no question. I stepped out into a thick October night, came straight to the hospital.

In long term couples, kissing releases oxytocin, the love hormone, which helps to build understanding, harmony and emotional closeness. Kissing a loved one can also boost serotonin, adrenaline and cortisol, which can regulate mood, boost focus and importantly, release stress.

The nurse adjusts something on the machine, gives me the palest of nods. I lean over the prone form I have watched slipping away for two years and press my lips to hers, and every sense explodes. I am furious and devastated, euphoric, cheated, torn. We are kissing at the front row of Xavier Rudd and someone throws a cup at us, we are liplocked around a straw under a Koh Phangan Full Moon, we are slow dancing and kissing at her bad actor cousin's wedding. And then rage. A ticker tape of torn photos of what our lives could have been, a carnival at the ends of the earth. A wedding, babies, homebuilding, all of it. I wanted to undress her under the outback stars, wanted to kiss her hard while she cradled a newborn between us, kiss her, kiss her until we were old and crotchety and still obsessed with each other’s onion-skin thin lips. I topple, buried.

A hiss, and the ventilator stops. She takes one, two rasping breaths and I catch them in my mouth, swallow them down deep into my bones and then everything is still.

And fall.

Then no more rise, no more fall.

Her mother presses her daughter’s fingers to her heart as though we were waiting for hers to stop instead, her father drops his head to her chest. The nurse looks away.

The heart, we were told, could keep on beating for hours, but it is less than ten minutes before her father sobs, his face muffled in her chest.

I step back, concentrate on pushing her last breaths into the deepest reaches of my body.

We linger, us three in the afterglow of her. We talk, we even smile, we share tears and a small bottle of Cointreau, her favourite. I lick the orange liqueur from my lips and for a second, they could be hers. Eventually, we stand, stretch our aching limbs, then we take it in turns to press our lips on her cold forehead.

You must keep in touch, says her mother, and I nod. And please, bring along anyone you - but we both look away.

In the car, grey silent tears fall over the steering wheel and my phone begins to vibrate again.

Seventeen missed calls, twelve unread messages.

I can deal with it, she says, as long as you tell me it wasn’t real, that it was just the biomechanics of a kiss.

2025 SHORT FICTION CONTEST JUDGE'S REMARKS

As you begin to read The Biomechanics of a Kiss, the first thing you will notice is the simply delectable prose. Effortless and beautiful, the author weaves lush images with a lived-in world that pulses off the page. This is a quiet story that is deeply emotional. It will leave even a gargoyle teary-eyed.

In The Biomechanics of a Kiss, the author accomplishes something very tough: the blending of two completely different tones while maintaining a balance that doesn’t remove from the impact of the story. In this case, it is the perky science lesson that is being taught in a voice reminiscent of the Mr. DNA animation in Jurassic Park, contrasted with the gut-wrenching emotional devastation playing out in first person through the rest of the story. It’s a tough line to walk, and The Biomechanics of a Kiss makes it look easy.

The Biomechanics of a Kiss secured itself a top-three placement through the genius inclusion of the narrator’s new girlfriend – a simple addition that complicates an already heartbreaking story and, rolling into the final lines of the piece, make the piece impossible to put down – even when it is over.

Elysia Rourke judged MoonLit Getaway's 2025 Short Fiction Contest.