Gustav and Serena get down to it high above Central Park

I twist round to face him. He's grinning at me. Interrogation over. He really does look like king of the heap. I know that he was seriously worried just then, and I've managed to soothe him. I grin back at him, put one finger on his chest and push him down on the sofa. My power is growing.

'Nothing's going to stop me now.'

He sighs deeply and falls back against the arm of the sofa, pulling me down with him. 'You know? Despite all their wealth and power I feel sorry for those Weinmeyers. I feel sorry for anyone who can't have you like I can.'

He's beneath me. We haven't turned the lights on inside the apartment, but enough light floods in from the city sky to outline his beautiful carved features, calm and relieved again. Life with him really is like battling over a stormy ocean. Raging surf, becalmed seas, whirlpools, some gentle snorkelling. And my Gustav and me, one at each end of a boat, sometimes a battle ship, sometimes a life raft, but always tipping, one up, one down.

No. No-one else is going to have me.

I see the silver chain hanging out of his pocket, and I snatch it up. Something heats up inside me like a filament. The desire to take over for once. The desire to work off this toxic steam. My lover's dark, chiselled face is in repose. The black hair, falling across his eyes as he lies back, his hands resting on my bare legs now, the fight gone out of him.

'So cock-sure, aren't you Levi? Shall I rock your world for a moment and tell you what might have happened if I hadn't been such a good girl this morning?'

He pushes his hair out of his eyes and gives me one of his straight, arrowing stares. 'Go on. Talk dirty to me. I dare you.'

'If they'd both had me at the same time.'

I crawl over him like a lizard. He lifts his hands to take my breasts as they dangle above him, but quick as a flash I wrap the silver chain tightly round his wrists, pull his arms up over his head and attach the end of the silver chain to the log-like legs of the coffee table.

'Silly girl. Think you're stronger than me?' But he makes no effort to struggle. Just watches me, in that way that makes me want to dance for him.

'I'm showing you what Mrs Weinmeyer did to her big strong tycoon of a husband. She handcuffed him, and then she mounted him.'

'Can a female mount a male?'

His black eyes are glinting but he's biting down hard on his lower lip to hide the grin. He tugs at the silver chain, but the heavy table doesn't budge and he's still attached.

'Oh, yes, she can. Just like this.'

My voice is soft, mesmeric, as I unbutton the rest of his shirt and yank it down his arms so that his elbows are trapped against his sides. I tickle the ends of my hair over his chest, over his stomach, see him shiver in response. Then I undo his trousers, as slowly as I can bear, letting all the anxiety drain out of me, replacing it with impatient supremacy. They rip down along with his boxers and I shudder with glee, my body warming in response as he springs free beneath me.

Again I tickle him with my hair, brushing it through his hair, around the shaft, run the circle of hair up and down until I see his Adam's apple jumping frantically in his throat. When he's rock hard, I brush over the balls already shrinking as his desire increases, and then it's time.

I straddle him, hold myself up on my knees above him as if praying. 'I wonder how it would have worked, technically? What do you think, Gustav?'

'Am I not enough for you, you little slut? You bored with me already? Maybe it was a mistake bringing you across the Pond. Too many new experiences. Too many new people.'

'Don't answer back, boy.' I slap at his buttock. I catch his chin in my hand, just like he does to me, and grip it tight.

I don't want to think about anyone else.

'You're a man of the world. Which bit goes where? One man. Two women. Where does the man fit into the ménage, do you suppose? I mean, I've never been with a woman, let alone a trois.'

'If I told you I know exactly how it works, it would be your turn to be jealous.' Gustav nips my finger, worrying at it in his mouth, still tugging at the silver chain. I see it biting into the crease of his wrist. I slap his buttock again, a satisfying sound. 'But two men, one woman? Much more fun.'

'Mr Weinmeyer didn't struggle like this. Oh, I forgot. She blindfolded him, too.'

I sit back on his thighs and fold my green silk dress into a strip. I hesitate before I tie it over his eyes. I love his eyes. Despite his best efforts to be unreadable, I am learning to translate each and every one of his expressions. Tonight's expression is ferocious, surprised lust.

I kiss him roughly on the mouth. Then I tie the blindfold oh so lightly, he could shake it off if he wanted. Then I ease myself on to him, oh so slowly, run my hands over his body, see his nipples prick up, feel the jump of him nearly inside me. He groans quietly as I lower myself inch by inch. My breasts brush over his mouth and he catches one, licks at it, then bites it, hard. Still fighting me. My body clenches tight with excitement, sucks him in, all the way to the hilt. It's so tempting to rush, but this is me. I'm in charge.

Now we have a sweet rhythm. He's with me, we're rocking together, and all the talk, all the input of today is fizzing through my head. I get an overwhelming vision of him in another life, cavorting with other women, maybe two at once, the jealousy mingling with a contrary lust, an urge to see it, to watch, to try something new, a woman, a threesome, whatever.

I grind myself over him, the flicker of the forbidden there again, another pair of black eyes staring at me, goading me from the sidelines.

I push myself at Gustav's mouth so that the pain will eradicate that other face. The jealousy is good, we can keep that, I can risk imagining those other bodies, because Gustav is mine, I'm the only one riding him, jacking up the rhythm, rocketing up and down. I need to ease these urges because it's too soon, too soon, but it's so intense now, my lover pulling against the silver chain as I grip him tighter inside and he thrusts so hard that I bounce off him.

‘Tell me I’m the best you ever had,’ I suddenly growl, leaning close to him. ‘I want to hear you say it.’

He shakes his head. 'You're a bitch on heat.’

I lift myself right up so that I'm just balancing on the tip.

'You want this or not?'

He lies still. I can't see him under the blindfold. I need his eyes on me, urgently, but I can't stop this, I flick myself so that he slips inside again and the pressure builds inside me, it feels so good to be on top. He draws back, tenses, and pushes hard and he doesn't stop until we can both hear my ragged gasps of pleasure but as soon as I start to shudder and scream he untwists his wrists from the silver chain, shakes off the blindfold, thank God it's him, and still inside me he hurls us both off the sofa.

Now he's hanging over me. 'Not so fast, young lady. And I'm going to do you right down here, my little slattern, because today you deserve an unforgiving surface.'

He pushes me across the cold floor and I relish the strength of him as my skin scrapes and squeaks and then he's coming too and the sound and the fury are over.

I rest my head on his chest, listen to the drumming of his heart. His arms are tight around me, our legs splayed on the rug. I kiss his throat and can't resist one last jibe.

'All we're missing is someone else to join in. What would you say, master? Would you allow me to try it?'

Oh, God. Why did I say that? Who am I talking about?

'Maybe. If I could vet who it was.'

There's one person we could never allow. What is the matter with me? I have to hound Pierre out of my mind before he does any more damage.

'And if I am there to keep an eye. Make sure you don't get too sharp a taste for it.' Gustav brings his hands down with a harsh slap on my bottom. 'But as the Miss Folkes journal of how to live says. Never say never.'