Sometimes I wish Tracey wasn't quite so extravert.

We've known each other for twelve months now, since final year at school. We're head over heels. I've never complained about the cheeky little stripteases she gives me, and now we're at uni I'm constantly on edge of 'coming' in the lecture theatre, simply thinking of her size C breasts with their pretty pink tips. 

But there are limits. We were only four weeks into uni when she announced: "Guess what. I've answered an advert and we're to do a performance. A hundred pounds each. What about that?"

"What performance? We're not musicians. What are we performing?"

"The advert said, 'to perform a live sex show before a private audience of some forty discerning gentlemen and ladies.'"

"What were you thinking of? Where did you see this advert?"

She never did answer that. She simply said: "You'll love it, Craig. You never have any problems getting it up and we perform well together. Think of the two hundred pounds."

"What do they say we've got to do?"

"They say we've got to be able to control our orgasms for at least twenty minutes. They'll give us a bonus for every minute over half an hour. Obviously, that means lots of foreplay, and we've got to make sure they see as much as possible, like not standing in front of each other and things like that. Do look more enthusiastic. It's going to be fun."

I was petrified. "If I get stage fright, what happens to my erection?"

"Just look at me. You always say I'm irresistible."

I did, and she was. She gave me that impish smile and provocative thrust of her boobs. What a minx.

"Okay, I'll do it."

"I gave them our measurements. They provide the costumes."

The venue was a select theatre with capacity for the 'forty gentlemen and ladies' of Tracey's advert. The plush cinema-type seats showed that the 'private company' was not short of money.

The stage was even more sumptuous. We would be 'performing' in a four-poster bed topped by a huge sloping mirror directed towards the audience. Those who wished would be able to observe everything we did as though from above. Opposite, stage right, was a large dressing table, also furnished with a mirror. The bench at the dressing table was backless, so Tracey's stunning back and ass would be on display to all.

As might mine...

Could I go through with this? There was still time. No audience had arrived as yet.

Between the bed and the dressing table was a low dais which, it was explained to us, would revolve if we mounted it. As the manager put it, in coarsest Yorkshire: "If you want to have a nude stand-up snog, stand on 't turntable...so we can all see everythin', like."

We were given our costumes in the dressing room. I was a businessman in immaculate midnight blue silk suit, but instructed: "No underwear." Tracey had the most expensive, royal blue and silver gown, of tight-fitting silk. The thought of her in that with nothing underneath made the whole project seem worthwhile, and the thought of 'erection to order' much more feasible. Blow the audience (no, mustn't think about them).

For the first part of the show, though, Tracey was to perform a 'little striptease' in a schoolgirl uniform of white blouse, pleated grey skirt, no stockings and the unsexiest thick grey cotton gym knickers you could imagine. No chance of an accidental camel-toe. Her cheeky, little-girl grin would have the men slabbering before she took anything off.

During this, I was to sit amongst the audience in my silk suit ('no underwear'). I soon found out why.

Approaching from the stage I saw the whole audience now assembled. The light was dim, but the sight horrified me. I couldn't bare all in front of these.

Surprisingly, and embarrassingly, both sexes were well represented. Nearly all were middle-aged or more and looking exceedingly worldly-wise.

The men looked slobs. Bloated, semi-retired businessmen. The proverbial fat cats. They looked as though middle-age spread and over-indulgence had left them so lethargic that perving over young people was all the sex they could manage, or be bothered lifting a finger or elevating a penis for.  But they were nothing like as daunting as the women. 'Cougars and Milfs', Tracey called them later (how does she know these things?). My only consolation beforehand had been the thought that Tracey, not my male self, would be the centre of attention. After all, she'd asked for it. But these women looked ravenous for dick, maybe because the men were so torpid. And the only dick on display was going to be mine.

I was led to the end of a row and made to sit next to a group of four such ladies, large of body, and greedy of eye. My neighbour could have been the chatelaine of a stately home, surrounded by toy poodles. She gushed as though I were one of her pets. "Oh, we're so glad you could perform for us. It's not easy to find young people willing to share their intimacy in this way. We're so looking forward to your little show. Especially if your lady is as good-looking as you."

The lights went down. Tracey danced innocently onto the stage as a CD played 'Boys and Girls Come Out to Play.' I forgot my surroundings and saw only her petite, pixie figure. Soon she began to undress. The breasts I loved so much were perfect as they appeared, apparently so shyly. The blouse and skirt came off. But not the knickers. Tight over her hips and ass, the grey cotton was too thick to do more than hint at any of her secrets. From the wings, she was passed a hockey stick. To the frustration of the audience, the topless schoolgirl played the ball around the stage in carefree delight, apparently oblivious to the male drawls of 'get 'em off.''

Even before she 'got 'em off' I became aware of the ladies beside me giggling and pointing at me. My neighbour was leaning back, allowing her friend to sneak a look. It was the bulge in my pants.

I ignored it for a moment, then became oblivious of all but the grey knickers as Tracey slowly rolled them down, revealing first the cleavage of her wonderful ass, and then, as she faced us...

I didn't realise I'd slid my hand inside my pants at this moment. What's a man to do after all? And it was so easy with no underwear.

My neighbour didn't miss a thing. She was looking at me and mouthing: "Get it out for me, dear."

I didn't need any persuading. It felt the biggest erection I'd ever had. The management evidently knew what they were doing sitting me here. Again my neighbour leant back to show me to her friend. Quietly they made me sit between them. 'Left-hand Lady' took my dick between her fingers and thumb, stroking it with care and experience. She knew what a disaster it would be if I came now. I panicked, thinking I might, but I felt safe in her control. To my right, feminine fingers were easing their way into my pants in search of my balls, When she found them, 'Right-hand Lady' knew deliciously what to do with them.

Tracey had finished her dance and sat naked at the dressing table, applying make-up ready to take the royal blue gown. Mysteriously the bench was designed to enhance the curves of any bottom that sat upon it. Never had this particular bottom been so ravishing.

Now she took the gown off the bed and slipped into it; the sophisticated opposite of the pixie schoolgirl. She glided elegantly to the front of the stage and beckoned me onto it. Hastily zipping up my pants I ascended, vainly trying to hide the bulge.

She stood, not in front of me but beside me. Deftly she reached for the zip I'd only just fastened, and gently but firmly pulled out my cock for all to see. She widened the zip to free my balls too. For a moment she stood, letting the whole audience peruse me while she was fully dressed. Far from Tracey being the centre of attention, the ogling of this mixed company of middle-aged connoisseurs was entirely focussed on my genitals, the only sexual items on display. While I waited to be swallowed up by the ground, Tracey knelt before me and began to suck and nibble at my foreskin the way I loved at home. Certain that the erection was there to stay, she undressed me. 

It was as she undressed me that I realised the whole experience, exposing my cock to forty gentlemen and ladies, was turning me on. I felt nothing now but the rush of juices as I stood there, naked. Yes, this erection was definitely there to stay.

She guided me onto the dais. Breathing; "Just follow me" she led me into our 'stand-up snog.' It was one of our most passionate clinches, our naked bodies moulded together, our tongues entwined, my dick pressed hard up between our bellies.

Slowly the dais began to turn. We could feel the audience's concentration on every move, every new angle. There was applause as we clasped each other's bottoms, even more at the mutual kneading of buttocks (she really has the most squeezable bum). Tracey began to stretch my cheeks apart, so I obediently returned the compliment, though surely they simply couldn't want to see...everything? The intensified applause showed they did. I could even hear female gasps of approval when it was the turn of my own ass to face the front, Tracey still stretching its cheeks open.

I could have stayed in this clinch forever, but Tracey gently swung us apart. We stood side by side on the 'turntable', hand in hand, like nothing so much as a naked Adam and Eve. She must have been compensating the company for a lack of full frontals during the clinch.

Now began the real sex. We sat on the edge of the bed, legs apart, so our masturbatory foreplay was clearly visible to all. I completely forgot the audience as my fingers clasped Tracey's mound and followed their own instinct into the warm softness between her labia. She needed no lubricant. She has a lovely little dimple at the top of her slit, which I can never resist teasing before I seek the real electric nub and before I plunge my fingers into her deepest, moist secrets. 

In our foreplay clever little Tracey didn't risk a premature finish, so only stroked my balls, leaving the cock clear for the audience to see. I looked up to see the hungry appraisal of the ladies I'd been sitting with. 

Dangerously stimulated now, I was relieved when Tracey rolled us onto the bed and lay on top of me. This was the real thing. We could almost forget the audience. They saw everything via the mirrors. We clasped each other tightly. Tracey cried out as she lowered her pussy onto me and I entered.

She exaggerated all her customary moans and happy noises for the audience's benefit. She lifted her body, sitting upright on my dick, her breasts responding to every move and thrust, driving me and the audience to distraction.

She lay down again and we rolled over to 'man on top'. Now, in the mirrors, the audience's focus was entirely on the thrusting of my ass, but I didn't care.

Tracey seemed to know the exact moment when my juices were in danger of spilling out of control. She stopped and gave me the shortest of breaks while she rose and set herself on all fours on the revolving turntable. She stretched her ass high in the air in preparation for a display of 'doggy position'. My role was clear. After three turns of the table, I mounted, knelt behind her and clasped the precious cheeks, while my cock sought its true home and entered into our final hot, wet act. My senses whirled. I had never made love on a spinning platform before, let alone before a company of gentlemen and ladies, however discerning. Eager to last as long as I could I followed my dick's urges to plunge deep into Tracey's vagina and enjoy her voluptuous squeezes, but also taking time to tease her clit with my tip, which I knew she liked, and which gave the gentlefolk more to look at. 

We evidently satisfied them. Tracey gave her loudest climactic cries. I came noisily at the same time. I withdrew and the audience applauded as Tracey cleaned up my cock with her tongue. 

We took our stand and bowed like old troopers. The ladies continued to stare, curious as to my subsiding penis. We returned to the dressing room where I confess I needed a moment to recover my breath. Tracey left the room before me but soon came running back. "Craig. We did it. We achieved the thirty-minute bonus. Forty minutes. That's ten minutes at five pounds each per minute. He said hardly anyone makes it over twenty minutes. And something else. He says we can come back any time we want. Can I book us for next term?"