It's the crop.
She is shrouded in darkness at the far end of the room, but faintly I see the silver sleeve of its handle glint in the light.
The crop is a good sign. I hope. The crop is everyday discipline, minor corrections, "encouragement", as once she called it. Outside as I waited, I'd feared the worst, the bitter, burning anguish of the dressage whip she most often chooses to punish offence. I've committed none, of that I am sure. And if I have, she has given no sign. But I have been sure before, and learned I was wrong. The glimpse of the crop gives me some comfort.
I know the rules of the room by now. I wait, till she whispers "Come!" from her chair. Then stepping forward, I kneel at her feet for her verdict, as she has taught me, head bowed, eyes averted, legs spread, palms open and upwards on my thighs, a display of open, unreserved submission towards her.
She is in the spiked heels she favours when she means to assert.
A vein in my neck throbs against the constriction of the collar, and as I look down I realise I am grateful, now, for the belt she has locked me into, with its wide leather strap and its stiff, studded pouch trapping my genitals, hiding them from view as well as from touch.
I wait.
Under my chin, hard leather stirs. It's not a surprise, I know at once what it is - the pleated butterfly at the tip of the crop, with the short knotted cord that adds weight and welts to its thin, flaring bite.
Slowly, insistently, the crop springing with tension, she raises my head up. I follow her pressure. I do not lead, I do not resist. I keep my eyes downcast, mindful now of glances stolen before. And the correction they brought.
At last, my head tilted back, the crop falls away. Now as she speaks, quiet and breathy, my hopes rise still more. There is warmth in her voice.
"Look at me now, David."
She leans forward into the light, her eyes bright and clear under arched eyebrows. Her make-up is discreet, her hair loose. Another good sign. It's when she is formal, prepared, her hair pulled back in coils, her eyes dark in shadow, that her intent is most ominous.
Her gaze is cool but the hint of a smile plays on her parted lips.
"I am pleased with you. There are no grounds for punishment."
I hardly dare breathe. My mind is a tumult. Relief, for sure, but more than that, a rising elation, a sense of pride, my own small share in the fulfilment I have sought to provide her.
She continues.