She moved above me, sliding down so that momentarily her arse cheeks smothered my face and I found my nose and mouth buried between her fleshy mounds. She pulled her cheeks apart and my face slid further upwards so that my mouth was pressing directly against her arsehole. She smelled sweaty and pungent after her exertions. I slipped my tongue out between my lips and flicked it against her puckered hole, tasting the sweat and the musky, slightly sweet aroma. Nadia pushed down on me, gripping her cheeks and spreading them even further, allowing the tip of my tongue to slide fractionally inside her arse. I waggled it to and fro, each movement sliding it further and further inside her until, finally, a good centimetre or so was gripped by her powerful sphincter muscles, trapped up her rear passage. My tongue ached as I thrust it forward, pleasuring my new Mistress, but she rode on, oblivious of my discomfort, heeding only her own desires. For a good five minutes, maybe longer, she bucked and reared above me, forcing my tongue ever deeper inside her.

Finally, as my jaw began to ache almost unbearably, she relented and pulled free from me, swinging her leg over my body and kneeling beside me. Exhausted, I looked up at my Master and Mistress, sweat beading on my brow and my face slick with Nadia's juices. My Master was still astride me, his cock throbbing in my hand.

"I'll take over that now," said Nadia, her hand brushing mine away from my Master. She motioned for him to move and he, too, swung his leg across me, kneeling beside Nadia and folding his arms around her. She turned and kissed him, stroking her hand over his cock. She looked down at me.

"Kneel by the side of the bed, Harriet," she said. Immediately, I rolled out of the bed and knelt on the floor. "Not that side, the other side," she said witheringly. Rising to my feet, I walked round the room and knelt, once more, at the side of the bed. My bed.

I watched as Nadia stretched my Master out along the edge of the bed and nestled behind him, kissing his ear and neck. Her right hand strayed down his chest and stomach, fingers rippling through his pubic hair, and finally alighted on his still erect cock. Laughing excitedly into his ear she gripped her hand around it and began to stroke its length, pausing occasionally to cup his balls and give them a brief squeeze and stroke her nails across them.

"Harriet, bend forward, look." I did, positioning myself inches away from my Master's engorged, purple helmet, observing Nadia's long, elegant fingers stroking intently along his shaft. A droplet of pre-cum hovered at his eye and his cock was quivering. "Kiss it, Harriet," she said.

I bent forward again and planted my lips against my Master's shiny, rock-hard head, rolling my tongue across the eye, drawing in the salty drop of pre-cum. Nadia's hand pumped his shaft as I kissed and kissed, planting miniature caresses across his entire glans. I licked upwards voraciously, feeling the gorgeous texture of the skin at the base of his head, sensing the heat rising from him, watching the miniature spasms along his length as the sperm readied itself for its expulsion.

Nadia started to pump his cock harder and faster, causing my Master to groan with pleasure. I could see his balls contracting rhythmically and knew he was about to come. My face just centimetres away, I readied myself for the explosion, knowing that it was coming in my direction. My Master grunted and Nadia began to pump furiously. A first, livid, powerful spurt erupted from him and spattered my cheek; there was a pause for a fraction of a second and then a second, longer spurt of come flew from his cock and landed on my nose. I tried not to back away or close my eyes, although it was difficult to avoid doing so instinctively. A third jet, long and trailing, landed on my nose and I opened my mouth wide, willing my Master's come to fly into it. It did: a short burst, and then another, and another, each one less powerful, burst into my mouth and landed on my waiting tongue. Nadia pumped away at my Master's cock until he was sated, until he had spent his seed on my face and in my mouth. I kept my mouth open to show my Master and Nadia what I had caught and then pointedly swallowed it.

"Very good, little Harriet," Nadia said. "Now then, that's me come, and your Master come. That just leaves you, doesn't it?"

This was music to my ears. Was I to be allowed to come, were my Master and Nadia going to return the service I had given them? Was I to be permitted to join them on the bed and seek release? I beamed at her.

"So stand up," she continued, "and let's see you come."

This wasn't what I had in mind at all. Nadia pulled the blanket over herself and my Master and they lay in the bed - lay in my bed - caressing one another and smugly watching me. I stood up beside the bed, suddenly cold and feeling very exposed, not sure what to do next.

"Come along, girl, get to it," said Nadia crossly.

Reluctantly, I lowered my hand to my pussy and rested it there. This was totally humiliating, being made to stand in the cold beside my own bed, while Nadia and my Master lay under the warm duvet and watched me wank myself. I started to fiddle with myself, trying hard to fight back the tears welling in my eyes, forcing myself to concentrate on what I was doing, telling myself that the sooner I did it the sooner I could get back into bed and forget about the shame of what was happening. It was hard, so very hard. I thought of the humiliation borne of what I was being forced to do. I put myself in their position and tried to see myself through their eyes: the poor little slave girl, made to pleasure her Mistress, forced out of her own bed, used as a receptacle for her Master's sperm and finally made to wank herself, in full view but so very, very alone. The powerful sense of shame shuddered through me, generating perverse feelings of excitement, and after a few minutes I began to sense the start of my climax.

Nadia and my Master were watching intently, their faces wreathed in smug grins as their slave girl performed for their delectation. My buttocks clenched as the first wave rolled through me, and then another, and another pulsed through my abdomen and stomach and womb, and the climax exploded within me, tearing at me, sinking its claws into my senses. I screwed my eyes shut and gave myself over to the moment, to the shame, to the knowledge that I had just performed such a lewd act for no reason other than that I was told to.

Harriet the slave girl had served her Master and Mistress. Again.