I wanted to shout at her, hit her, berate her for turning my life upside down, inside out and round about; I wanted to yell about commitment and love, and trust and respect; I wanted to tell her that I had fallen for her, had given myself over to her, entrusted myself to her, only for her to disappear without any more thought than a hastily scribbled note; I wanted to knock sense into her, belt lumps out of her, make her accept a sense of responsibility. I wanted to do all those things.

But in the circumstances, post-climactic, with her brother still stationed at his post, the marks of his subordination clearly evident on his exposed rump, I realised I might not be on safe ground for a moral attack.

"Welcome back," I said. "There's wine chilling in the fridge."

Fetishdoll threw her head back and unleashed a mighty laugh, a great heaving snort accompanied by a throaty, breathy snigger. "Sweet Harriet," she smiled, "I might just change you yet." As she barged into the kitchen, the swaggering, blustering, clumsy opposite of her sibling, Paul took advantage of the lull to emerge from his refuge beneath my skirt. His face was as red as his arse, though I wasn't sure if this was through exertion or embarrassment. Wordlessly, he gathered his clothes and ran to his room, narrowly avoiding the returning Fetishdoll.

She looked wonderful. Wherever she had been, it had been beneficial. The blue-green hair dye had been replaced by jet black, which accentuated her pale skin and emphasised its softness and purity. Her beads, dozens of them braided into the tresses, were still there, still clacking dementedly when she moved her head, still drawing attention to this dazzling creature. As though she needed any artifice to draw attention to her: she had such presence, such assurance, she would always dominate a gathering. I laughed inwardly at my ham-fisted attempts at being a domme with her brother Paul: Fetishdoll was the real thing, a natural, unaffected superior, whose strength of personality drew people to her, who could make people do anything for her, without really trying.

She was as skinny as ever, but she appeared to be more toned than before, and I suspected she had been working out. She was wearing a characteristically skimpy tee shirt, and her breasts, tiny, uplifted breasts with invitingly prominent nipples, formed an arresting sight, particularly given the curious bulges which I knew to be her nipple rings. An expanse of her stomach was exposed beneath the crop top, including her belly button which, too, I noticed, had been pierced: that was new. She was wearing body hugging jeans, with the material folded into a sensual vee around her crotch, drawing ones eye inescapably towards it. She stood, waggling the wine bottle and three glasses, hips swaying coquettishly. It was happening again, I knew it. No matter how angry I got with her, how sincerely I convinced myself that she was too unreliable to bother with, that I had to break all relations with her, as soon as she reappeared all my resolutions dissolved and I found myself falling under her spell once more. She did it every time. And she did it again now. There was no way out.

"So where's little brother," she drawled, uncorking the bottle. "Putting lotion on his poor butt?" She cackled again, as she poured the first glass. "Guess you've got some explaining to do, girl. What d'you think you're doing, beating on my baby brother?"

I started to gibber, not really knowing what to say. After all, what do you say, in such circumstances? "Sorry," I muttered finally.

She waved the apology aside. "Whatever. Expect he deserved it. Always was a pain in the ass, now he's got one. So what is this, then? Is he your sub?"

Put like that, so baldly, so bluntly, it sounded vaguely shocking, and my initial instinct was to deny it, but let's face it, he was, wasn't he? Little Paul, who tidied the house, saw to my needs, got a spanking when he misbehaved and had to service his Mistress. What else was he but a sub? Not for the first time, though, I wondered how I had got myself into this. I was just a quiet girl, albeit with a fairly explosive temper, but never, until this mad woman had entered my life those few months ago, had I gone in for anything like this. And here I was discussing the finer points of domme etiquette with my muse.

On cue, Paul returned, showered and with a change of clothes: Mr Clean strikes again, I thought. He sat, somewhat gingerly, on the settee, wincing as he did, which provoked shreiks of laughter from Fetishdoll and me.

"D'you want a drink?" I asked him.

"Goddamn, Harriet, you're the politest damned domme I ever met. Hey you, pour yourself a glass, a small one, and refill ours while you're at it."

Paul did as he was told. He appeared, if anything, to be less embarrassed than me, although I thought this must be a freaky situation for him to be in, caught in flagrante by his older sister. Not only that, but caught in flagrante with someone he knew to be his sister's lover; and not only that but caught in flagrante in a fairly compromising and humiliating situation. But he didn't seem to care.

"Well then," said Fetishdoll, raising her glass, "bottoms up, as you Brits say. An appropriate phrase."

We drank to ourselves, looking from one to the other: brother to sister, lover to lover, submissive to Mistress, as curious a ménage à trois as you could hope to meet. I felt my heart pounding in my chest. Sometimes you know you are living through something momentous, sense that what is unfolding will have major repercussions for the rest of your life. This was one of those moments: things were changing, things were happening, this was a turning point for all of us.

"So," said Fetishdoll, draining her glass in one and rummaging in her bag, emerging with a block of dope, tobacco and some Rizlas, "let's get some ground rules here. Not that I'm a great one for following rules, but you two will. He is your sub," she continued, gesturing first at Paul and then me, "that's cool. You can do whatever you want with him, whenever. He'll like it, I know him. You need to be firm, but you'll get there, with a bit of practice.

"He can sleep in his own bed, in his own room. When you need him, you can call him through, no problems. I'll keep clear and let you get on with whatever you want. We'll be sleeping in our room together," Fetishdoll concluded, gesticulating at me again, "so that we can pick up where we left off before I had to go. I've got some new moves to show you," she grinned.

Hmm, I thought, this sounds to me like a takeover. "Well," I said, "you make it sound like I'm your sub as well, bossing me around, telling me what to do in my own house."

"Oh no, sweet Harriet, you're no sub. Not you. You're one hundred percent domme, girl, it's built into your character. I spotted it first time I met you. It's just that you're a domme who thinks she wants to be a sub. That's what makes you so interesting. That's why I love you so much."

Okay, I challenge you, how do you answer that?