I've had my suspicions about Isaac for a few months, but always from a relatively safe distance. His sheer intensity up close makes my veins pulse harder. All of a sudden, instead of being just a colleague or a friend, he represents power. Danger. Unpredictability. It ought to scare me, well, it does, but in a good way.

He's still dressed. I'm not, my bra and panties askew from masturbating in them while Jessica photographed me and he watched. He still has a prominent hard-on as he stands and leads me by the hand across the airy studio space.

We pass the bedroom scene and stop at the partitioned area containing the lounge. There's a simple red sofa in the middle, a white sheet stretched up the wall a few feet behind it, and a couple of lighting poles either side, pointing inward. Jessica swaps out the memory card and follows us, camera primed. The fact she's going to photograph what happens next adds to the thrill as well as somehow validates my actions. For me, this is monumental. For her, it's just work, and her lack of reaction keeps me grounded.

He stands me dead centre in front of the sofa. Moves in close behind me until his breath is hot against my ear. Each scuff of his clothes against my bare skin tingles. His whisper is soft. “Are you sure you want this?”

I'm honestly not, so I don't move. Do I want this? I barely recognise myself at the moment. But I'm coming to realise that although I love Thomas and want what we have for us, this...? This, I want for me.

Isaac's whisper in my other ear startles me. “Last chance, Chloe.” I shiver as his lips brush my lobe. “Do you want this? Just say the word and it stops. We can leave right now.”

I find my voice inside a shaky breath. “What are you going to do to me?”

He takes his time answering, allowing his slightly irregular breathing pattern to give away his own mounting desires. “I'm going to treat you. Uncover your inner wants. Show you pleasure like you've never known. I've wanted you for so long.”

My breath stutters and he shifts again, placing his hands possessively on my shoulders and taking up residence in the other ear, an edgier tone like the devil just occupied him. “I’m going to hurt you.” I flinch, adrenaline spiking.

He relaxes his grip and massages my shoulder blades. “Last chance. Do you want this?”

It's a very good question. Last week, yesterday, an hour ago I'd have said no. But now I have this beat inside me. A thrumming pulse radiating and lighting my skin from deep down. And my fear of the unknown is eclipsed by my need to know. To rediscover the confidence of my youth. Perhaps this is the way to do it? To unlock it.

I take another shaky breath and step forward away from him. Then another. And another until my shins touch the sofa. I turn and sit, demurely on its edge. Slide my gaze up to his and watch the smile form.

He follows my steps until he's standing to my left. Reaches down and strokes my cheek. “Good girl.”

I roll my face into his touch. Sigh. Barely react when he tilts my chin up. But then his lips land on mine and I gasp and respond, lips mashing, tongues exploring, fresh wetness forming in my underwear.

When we come up for air he smiles down at me. “You're mine now.”

I shiver and he pats my cheek, thumbing away a strand of hair. “Now take off your panties.”

He stands fully and we lock gazes. I breathe. “What if I don't want to?”

Air draws in through his teeth. “Then I will take them. And you won't like it.”

Neither of us move, save for chests rising and falling. He nods, like he's assessing the landscape of our emerging dynamic. “Take off your panties, Chloe. Don't make me ask a third time.”

On unsteady legs, I rise and slip my thumbs into the waistband. Push them to the floor, step free and pick them up. I don't want to sit again in case I leave a potato print of arousal on the upholstery.

Isaac holds out his palm. I shake my head, slightly scandalised. He doesn't move, merely raises his eyebrows, and I stare, then hand the parcel of warm fabric over, cheeks reddening.

Like unwrapping a precious gift, he unfolds the material and holds the garment up between us. My arousal has stained the centre and he brings it close to his face. I redden further as he inhales, though I can't help but be a tiny bit pleased as I notice his bulge straining.

Satisfied, he spreads one of the leg holes and slips it over my head. He twirls a finger in the air and I turn away from him, my shapely arse a few inches from his groin.

Scooping my hair free of the underwear noose, he arranges them so the gusset rests against my throat then bunches the underwear behind my neck and twists quickly. Once. Twice. Three times.

I gasp as the material tightens around my throat, sticky arousal depositing and smearing against it. Keeping the panty choker tightly held in one fist, he bends me forward and the retort of a single, meaty slap to one of my arse cheeks echoes before the sting and heat registers inside me.

I yelp. The sensation of the hand print forming on my rear is as shocking as it is arousing. When I wiggle my bum to use the cool air in the room as an antidote to the spreading warmth, my inner thighs glide together with fresh juices.

He hauls me upright by the panties and hisses in my ear, “That was for making me ask twice.” He shoves me forward again and launches a searing slap to the opposing bum cheek, then hauls me up again. “And that was for making me wait. I won't be so gentle next time.”

I whimper as the heat floods. “S… sorry.”

“Sir,” he adds.

“What?”

“Sorry, Sir.”

I roll the idea round my mind and shake my head. “I'm not… I… no.”

He doesn't pursue it. Lets me stew in my thoughts. And I have many.

I think I like the idea of BDSM. Not the whole rubber masks and ball gags and caning—that's not for me—but the principles behind one person being in control and the other submitting.

After my husband slapped my arse that one time, I'd looked up online what it meant to get wet from it. That was an eye-opener. And honestly a relief to find it wasn't just me.

With curiosity piqued. I'd researched more. Discovered a whole subculture, some arousing, some definitely not. Stories about women doing their chores in the nude to be kneeling by the front door when their man came home from work were definitely not what I was about. So it annoyed me that parts of that idea aroused me. Not the servant part, but the physical aspect of being under someone's spell. Relinquishing control in a safe space to see what happened. What it would do to me.

It was about that time Isaac joined the department and we hit it off. He was intellectually on par. Shared a shameless love of 90s Britpop. Didn't say much but when he did, it was well considered. He felt… equal. And yet there was this darkness I'd catch sometimes as we'd be sitting opposite one another in boring meetings. Something about the way he looked at me let me know his mind was very much not on work.

Isaac interrupts by pushing me forward to kneel on the sofa. I stumble a little but he keeps me upright by the panties around my neck.

His voice is gravelly in my left ear. “Be a good girl and hold these for me. I need both hands free.” He grabs my wrist and transfers the grip he has on the underwear to me. “Keep it tight now.”

It's both humbling and electrifying to be kneeling for him and choking myself. I'm consumed by anticipation, focusing on a tiny mark on the white sheet behind the sofa as he appraises me. Strokes my bottom. Brushes my hips. Silent, save for the occasional click of the camera shutter.

A shuffling behind me turns out to be him sinking to his knees. A hand on my foot lifts it slightly for him to nuzzle my sole. His lips skim, then he nibbles the toes. It makes them fizz. Nobody has ever paid attention to my feet before and it's as unnerving as it is exciting.

He stands again, trailing one hand up a calf then a thigh to cup and rub my bottom. It's soothing. Erotic. I sigh and emit a low moan.

When his hand leaves my skin, I think I know what to expect but the reality is so much louder as it lands. My arse cheek stings like crazy in the aftermath and he rubs to soothe it.

Heat races to the contact point, draining everywhere else of warmth until more rushes in to replace it. I think I scream or squeak or something, but I can't be sure. My entire focus is on that red welt.

He lets me savour it. Bask in it. His hand is soothing and I purr at his touch. Jessica makes sure she documents the moment but the camera can't see the juices running down my thighs.

With a final rub, he swings his arm back and crashes it into my rump. Same side. This time I definitely scream. Rock my hips to escape the pain. His hand cupping my reddening cheek and stroking it offers no respite. In some ways it's worse, because the very tool used to inflict pain is the one to reduce its effect.

If my head registers pain, my pussy responds with delight. More juices form and drizzle down my thighs. There's such a disparity between what I think I should like and my actual response. It's confusing and unexpected. My instinct is to tell him to stop; yet I also want more.

My brain can barely process the emotions when his hand leaves my skin and I reflexively brace for impact. When it doesn't arrive, I relax and that's when it lands on the other cheek. I howl. I drip.

Each slap that lands sends my thoughts spiralling. If I ask for more, what does that make me? Will it show I'm strong enough to withstand it? Will he respect me? If I just take it, am I somehow inferior, needing the dominance of this man to be whole?

As more slaps rain down though, the heat spreads and kind of blankets the noise. When the barrage of slaps draw to a close and he slithers his hand between my legs, his fingers pull away, dripping.

“You like that, huh?”

I remain quiet. I'm still processing. Even when I hear him licking his fingers clean of my juices and moaning, I'm torn between diving into a hole of shame and asking for more. How can we discuss marketing strategies on Monday when he knows that this particular brand of pain turns me on.

“Well? Do you like it?”

I falter and offer a small voice. “Yes.”

He draws a wet fingertip over the inflamed markings on my rear, a stark reminder that it's going to hurt tomorrow.

“And do you want more?”

I'm not even sure the voice that responds is mine. “Yes.”

“Yes, Sir,” he reminds, grabbing the panty choker off me and twisting it tighter.

I gurgle but the word won't come out. I can't take everything in. It's too much.

He keeps the pressure up for a long moment then lets go and I suck in air, the panties slack.

With tenderness, he removes them. No idea where they end up. He unhooks my bra and slithers it free then tosses that away too.

“Turn around. Let me look at you.”

I do as he asks, forearms automatically crossing in front of my tummy, palms covering my pussy. He shakes his head and waves them aside. Like some damn spell, they end up at my sides and he steps back to appraise me.

“My god you're beautiful.”

I redden again. Shake my head, staring at his feet.

“Say it,” he urges.

I can't bring myself to do so. Instead, I slide my gaze up his length, lingering on his perma-bulge. Up over where his T-shirt ripples with the physique it hides. I meet his eyes, the understanding in them warring with impatience and I can't help myself. I smirk and repeat, “My god you're beautiful.”

He slaps a breast and I shriek, rubbing the strike point and staring. Calm as a lake, he states, “Try again.”

I shake my head, still reeling at the audacity he had to lash out.

Calling over his shoulder, he asks, ”Do you have a mirror, Jess?”

“Sure. Hang on.”

She steps in and hands the camera to me. Winks. “These might change your mind,” then she paces away.

I review the photographs. Gasp at how they portray me. Vulnerable yet sexy. The vibrant colour that forms on my bottom as Isaac unleashes the spanking makes my heart flutter anew.

Jessica returns carrying a full-length free-standing mirror and positions it alongside him. He points at the floor in front of it. Handing the camera back, I step up. Lift my gaze and take in the reflection.

It's not a view I'm accustomed to. I actually can't remember the last time I looked at myself from anything but the head up when I'm applying make-up. I tremble.

“Chloe.”

“Yes.”

“You're beautiful. Admit it.”

I trace my hands up my sides. Down. Brush my belly and stop. Bite my lip. “I guess I'm alright.”

I flinch, expecting a slap, but nothing comes. When I glance across, he’s smiling. “Getting there. But we can do better.”

Isaac strides over near the entrance and fetches my bag. He dumps it nearby, unzips it and rummages. Pulls out a black T-shirt and panties. “Put these on. We don't want to make a mess on Jessica's couch.”

I'm only too happy to cover myself and, as I slide the panties up, I'm acutely aware of my butt.

When I'm presentable, I stand before him. Eyes level, meeting his penetrative stare. I slide my hands behind my back and cross my wrists. He smiles.

“What do you want now?”

I bite my lip. Sway my hips a little. “Ummm. I want to feel your hands on me.”

“All over? Or anywhere specific?”

“Well I kinda liked it when you… rubbed my bum.”

“That could be arranged. Anything else?”

I shuffle from foot to foot. “I’d like you to… to…” My voice catches, “spank me.”

“Sir,” he reminded.

I say nothing for a long moment and when I do speak, it’s barely a whisper. “Please spank me.”

He nods. “Very well.” Points at the couch.

Turning away from him, I crawl on and lie flat along its length. “Like this?”

“Perfect.”

He starts at my ankle and glides his hand all the way up until he cups my arse. Jessica captures the moment of tenderness before I suspect the storm. But he surprises me. Squeezes gently. Waits for me to finish wriggling up into his palm.

“Why do you want me to spank you, Chloe?”

Another good question. I consider before answering. “When you did it earlier, it was like, I don't know... all thoughts seemed to vanish and I was focusing only on your hand.” I pause while he strokes my bottom through the material. “You've seen me at work and know how I act strong. But I also overthink things. You kind of took all that away. It was calming, which sounds crazy considering how fast my heart was hammering. Does that make any sense at all?”

“None whatsoever.” He chuckles and so do I.

When he issues a playful slap, I sigh. “Yeah, just like that, mmm. More please.”

Isaac slides the hand from my rump up my back, curls my hair into a ponytail and tugs. “Sir,” he reminds.

I moan when his free hand stings my rear. Even though it's covered so the effect is lessened, it still smarts. Again and again he strikes, barely a breath between them as I growl a sustained moan and push my bottom up to offer more of me.

He rubs it, setting off sparks inside, then cracks me harder on the other cheek.

“Ohhh God, yes.”

The glow increases and I know it's going to make sitting a stark reminder of this moment, but it doesn't stop me. Words tumble from my mouth. “More. Harder! Ohh, yeah. So close. So close.”

After a particularly vicious slap, he tugs the knickers below my glowing rear then remains in contact, sliding his hand down between my legs. I part them voluntarily and he cups my leaking sex, smearing up as a balm to my arse, then issues a barrage of bare, wet spanks that echo into the studio ahead of my groans.

Sliding his hand beneath the soaked panties, across my labia again, he leans down and pulls my hair so my ear is level with his harsh whisper. “Is this going to make you cum?”

“Yes!”

Sawing a fingertip between my soaked folds, he nudges my clit and I buck up into the touch. He nips my earlobe. “And did I give you permission to cum?”

I freeze. “N… no.”

He pats my pussy. “Then don't.”

With gentle pressure, he slips a finger inside me. Pulls out. Invades again. Starts to fuck me as the pressure builds and I whimper, clamping my thighs around his wrist in a futile effort to limit the mounting pleasure. “No… oh God. Can't hold it. Can't hold it. Fu… can't hold it.”

Yanking free as I crest, he spanks my arse and I howl. My pussy starts to spasm and I fight against the pressure, bucking and rolling my hips. His command is through gritted teeth right alongside my ear. “Don't cum. Only sluts cum. You're not a slut are you?”

The tremors pulse and flutter and I squeeze as hard as I can to stem them. I've never edged this hard, nor for as long, in my life, barely holding on, whispering, “Please. Pleeeease. I need to cum. Please ohh.”

His grip tightens around my hair and he thunders, “SIR!”

“S… ohhh, fuu…”

He forges fingers down into my sodden slit again. Fucks me furiously, pulls out and digs, circling my clit with a dripping digit. I convulse. Clamp my legs shut. “God, oh God no, can't hold back. Please… pl… ohhh.”

Worming two fingers back into my soaked snatch, he fingers me and I lose control. My pussy quakes and pulses around his buried fingers. My frame is racked with beats of pleasure, laced with part dread at failing him, mostly elation at finally getting what I need and I snarl into the space as the orgasm claims me. He claims me.

The climax is like nothing in my life before. It swamps me and flashes through my body in a series of shockwaves radiating from where his fingers rest. The dull clicks of the camera barely register. All that exists are his measured breaths in my ear and the rampant heat that connects his entry point with every inflamed skin receptor that frantically absorbs the cool in the room to douse it.

I let it consume me. Ride the exquisite endorphin rush for as long as it takes, as long as I can, until the flutters begin to dissipate and I relax into a blissful contented soup.

He releases my hair, strokes my cheek, withdraws and lets me rest; bask as he traces sticky fingers up and down my spine, grounding me.

Only when he rolls my panties back up into position do I stir and attempt to roll over. My bottom is tender when I sit and each brush of the sofa against it ignites a memory of being under his command. It's fascinating and sexy and alluring and I'm not sure I can ever get enough.

He smiles down at me. “I take it you enjoyed that?”

I nod, still dazed, orgasmic flotsam bobbing inside me.

Jessica approaches and offers the camera. I review the shots and squirm. She's captured every facet of our dynamic. And even—horror of all horrors—my ‘O’ face. But as I step through and relive the scene, it becomes apparent how much raw sex she's packed into each frame. It's beyond exciting to think that I let myself go as far as I did.

Isaac observes. “Now do you believe you're beautiful?”

I half nod. “I believe you think I am. And that's enough for me. Thank you. That was seriously... incredible, wow.”

Standing, I hand the camera back to Jessica. His clothes brush my comparative nakedness and I shiver. He steps back and appraises me. Our eyes meet and I search his expression. Looking for… I don't know. Something. His impassiveness is frustrating.

“Aren't you mad?”

Cocking his head, he studies me.“Why would I be mad?”

Swallowing hard, I bite my lip. “Because I failed you. I came without permission.” I avert my eyes. Look at the floor. Shuffle from foot to foot. “And I can't help but wonder what… what do you do to girls who fail you? To sluts who fail you.”

I slide my gaze up to meet his, and add. “Sir.”