Karen and Beth were sisters who for all their lives had competed against one another, being born ten months apart they were in the same class at school. They competed over everything, from grades at school to attention from their parents at home and everything in between. Their parents were strict Catholics and brought their daughters up the same, although their competitive nature often took priority to them, over their parents' religious direction.
Growing up both girls spent lots of time with their next door neighbour, a girl called Emma who was the same age as them both.
It was this rivalry that had led them to their current situation. After bumping into them after two years of no contact and seeing that their rivalry had not even slightly abated, Emma had suggested a competition where she would handle the organisation and the winner would finally for once completely outdo the other. Of course they both agreed and Emma had made all the arrangements including getting details of their monthly routines & medical records. It's impressive what a cash bribe of two hundred could get from the underpaid staff at the medical centre. Neither Karen or Beth were aware that Emma's parents were moving to the other side of the country in a few days and Emma had secured a job once she graduated university near where her parents were moving to.
After a journey where both sisters were blindfolded they were led into a mirror lined room, where the only furniture items were two leather benches spaced a few feet apart from one another. A few moments later four women and two men entered the room from a door opposite. The women were dressed in white uniforms akin to salon beauty treatment staff and the men were dressed in white linen trousers and shirts. The men both wore venetian style masks that covered them from forehead to just under their noses. Each mask was completely plain to give no clue as to the identity of the wearer.
Karen and Beth were directed by separate screens to remove all their clothing in exchange for paper thin gowns that covered them from neck to knees. Once changed, each was led back to the centre of the room.
The two men walked to the centre of the room and their 'assistants' seductively helped remove all their clothing. Both men were around 6'0 tall, well built and very pleasing to the eye. Once naked, each guy lay down on a bench facing in opposite directions.
Karen & Beth were urged to straddle the guy beside them. Each one started to have real concerns at this point and they were slow to move so Emma spoke up.
"Come on girls," Emma said, "you wouldn't want to lose now and let your sister win would you?"
Both girls looked at each and their competitive nature took over. Seeing the chance to beat their sister prompted both of them to straddle their men. The women assistants stood beside them, started to push them down by the shoulders. Then men at this point were using their hands to apply lubricant to themselves to ensure things went in smoothly. Once each sister was fully seated on 'their' cocks Emma began to explain the rules of their task.
"Karen, Beth, your objective here is simple, neither you nor the young gentleman you are sitting on are to reach orgasm. If either of you do reach climax then you lose this challenge. Since I'm sure you could probably sit there all night with no risk we had to make this a little more challenging. The gentlemen that you have inside you both took two Viagra about forty-five minutes ago so there is no danger of them underperforming. Next the women beside you are going to do their best to drive either you or your man to orgasm. They are not allowed to touch your breasts or pussies nor are they allowed to touch the men's cocks, but anything else is fair game. Now I want you to consider what will happen to your sister if she loses, since I know from your medical records that neither of you are on the pill, and you both are about mid way through your cycles coupled with the fact your parents are devout Catholics so should your man climax inside you, in nine months they would definitely not be comparable in figure or looks. If you orgasm before your man does, you lose, and we will hold you in place until your man cums inside you. If either of you attempts to get up before one of you is declared the winner, the women here will push you back down and hold you in place until the man underneath you cums. If you both understand and have no questions we can begin at the sound of the tearing."
Each sister listened and was momentarily confused by the tearing comment, but the women around each sister had gripped the sides of the gowns and pulled. The flimsy gowns split as designed and left both sisters naked astride and impaled on a cock.
Despite the obvious risks involved and the common sense precautions being completely overlooked the idea of seeing the belly of the other sister swell was far too appealing so neither tried to dismount. Instead they both sat there waiting to see what would happen, both trying to hide their nervousness.
Any notion of dismounting or getting off was quickly dismissed as that would break the rules Emma had explained and result in their immediate loss.
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Each sister could feel what was done to them and see it happening to the other as the four women had been instructed on what to do and when, to try and choreograph the actions.
The women in twos moved behind each sister and began their efforts. One started off stroking up and down Karen's spine with light movements that were gradually increasing in pressure becoming a firm back rub, whilst the other moved her hands to the woman's neck and began to trace her nails around the neck, her cheeks and her jaw line. The other two women were mirroring the actions on Beth.
The woman paying attention to Karen's back began to alternative between firm movements and light sensual strokes varying where they were administered. Both sisters were responding well to these ministrations and were starting to relax. The second woman then started to move her hands down Karen's sides then round her front towards her waistline ensuring she went no lower as that was agreed not to happen.
Both men started to move their hips causing Karen and Beth to start breathing heavier and start grinding back against their partner. The women started to stroke Karen and Beth's arms, nudging them forwards, then gently lifting them and manoeuvring them until both Karen and Beth were stroking their own breasts with their heads tilted back.
Seeing their actions were having an effect the women acknowledged each other with a glance and returned to their plan. Whilst one woman continued to stroke Karen's body, the other leant in close to her ear and started to whisper, so quietly no one else in the room could hear what was being said.
"Can you feel that hard cock inside you2?" she asked, "I bet that feels really good. Is it stretching you? I've been helping him recently, taking that cock in my mouth, running my tongue over it, but I wouldn't let him cum. I've been doing that for over a week now, but not letting him have any release. Can you imagine how full his balls are, how desperate he is to cum."
Looking over through lidded eyes Karen could see another woman leaning over Beth whispering in her ear. By this stage both women were squeezing their breasts and stimulating their nipples. Both were moving their heads back and forth, their breathing speeding up and their hips moving constantly.
Next one woman moved from 'their' sister to the man lying beneath them and started to whisper in his ear.
