The Mother of Invention

Under the covers, Dawn lay on her side, sliding one hand down the front and the other, with a dollop of spit, around the back. She pressed on her slick anus as she rubbed her clit, bringing herself to a second crashing orgasm. She fell asleep almost immediately thereafter. Images of her big, round bum, jiggling tantalizingly and getting pumped deep by a thick cock, danced through her head all night.

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One wall away, Maria dreamed too. First came a disturbingly sexual vision of rubbing her pussy while she watched her daughter, on a bed nearby, getting her rear end penetrated by a long, thick penis, screams of pleasure and pain filling the room. Next...she dreamed of exercise bikes. She awoke in a sweat several hours later, her mind swimming with blueprints and drawings.

"Holy shit," she gasped to herself as she sat up in bed, her breasts glistening with sweat in the hot room. She pulled on a nightshirt and slippers and scampered down the steps into the cool basement where her light table and workshop were. "They don't pay me to be an engineer for nothing." she muttered, taking out a pencil and examining the end. Satisfied of his sharpness, she began to draw.

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"What have you been working on down there for so long?" Dawn asked, coming in the an arm-load of groceries, "You've been practically living in the basement for two weeks! Why can't I go down there?" She stamped the snow off her boots and handed the bags to her mother before unlacing the heavy rubber shoes and putting them on the drying rack in the mudroom. Maria wore a tight-fitting t-shirt and red lace panties. In her book, "fully clothed" was something for the outdoors. Dawn followed suit, and kept shedding her warm winter clothes until only a bra and panties remained. Maria gave a naughty smile.

"Well," she said in a soft voice, "Why don't we step into the living room, and I'll show you?" Dawn gave a suspicious smile.

"Alright," she said slowly, looking sideways at her mother as they walked into the living room, boobs bouncing heavily. Two large forms that had not been there when she left for the grocery store were situated in the living room in front of the windows, covered with sheets. Maria was plainly very excited, and bounced around the room like an excited little schoolgirl.

"OK, you know that night we got drunk and got ourselves off to that porn a couple weeks ago? The one with the girl getting it in the butt?" Maria said.

Dawn laughed. "How could I forget!" she giggled.

"Well that night...I had a dream. It was some crazy combo of all that stuff that happened that night...plus the alcohol...[Dawn laughed and blushed]...and I woke up with all sorts of ideas in my head. I knew I just HAD to build what I had dreamed of!"

"So that explains all the welding," Dawn said, peering over her mother's shoulder at the sheet-covered forms.

"So I remembered that anal hurts. But some women do it and they love it! So I figured I might have been doing something wrong! Then I remembered how much you seem to love the idea, and how much you seem to want to try it. And, I'll admit, how sexy I thought you would look with a cock in your culo." Maria said quickly. Dawn laughed hard.

"OK, OK, get to the point!" Dawn said excitedly.

"And then!" Maria said, getting there, "I remembered the exercise bikes!" She seemed to have lost Dawn, who shot her a quizzical expression. Maria rolled her eyes.

"Just look," she said. She bent and took hold of a handful of sheets. In one quick flourish, she drew the sheets off of two shiny new exercise bikes. But these were no ordinary bikes. Maria watched with a broad smile as her daughter's face broke into a sparkling grin of excitement and understanding. Maria had modified the bikes. A lot. A second sprocket and chain, apart from the fan, hooked up to a small, chain-driven compressor. This, in turn, was hooked up to a small hydraulic ram that had a heavy, cylindrical lead weight sitting on top of it. An arm and lever system attached to the ram head powered the movements of a long dildo, which emerged through a hole in the specially-remodeled seats.

"Mom...oh my GOD!" Dawn said, rushing forward to examine the apparatus.

"See, you pedal the bike," Maria began, pointing out various parts, "And depending on where you set this dial (the numbers are depths, in inches), the ram will descend to a certain point, pushing the dildo up, and-"

Dawn didn't hear the rest of her mother's complicated engineer's jargon and explanations. She only had to understand one thing.

"So the faster you pedal, the faster you get fucked in the ass?" Dawn said, eyes wide with excitement. Maria smiled.

"Precisely. And you can set how deep you want to get it, so you can work your way up! This way, we get pleasure, exercise, and anal lessons all in one. I even added these things here [Maria indicated some apparatus attached to the frame and handle bars that Dawn didn't recognize] so that it has a sort of "challenge mode"; you have to keep a pace for a certain amount of time, and if you start to slow down, the dildo starts to go up, and doesn't stop going up unless you pedal faster. That's 10 inches of cock up your butt!" Maria said excitedly. Dawn laughed nervously.

"I think I'll start out on the lower settings, thanks!" she said. Maria was still musing out loud about her design.

"I was thinking of attaching the drive arms straight to the main sprocket, but it would have created too much friction on your little hole, even at slow pedaling speeds..." she said.

"Can we try them out? Now?" Dawn broke in, a bright, eager grin on her face. Maria grinned back.

"I'll get the lube, you get naked!" she said, running off into her bedroom. She returned carrying a box, on top of which was a large bottle of Astroglide Gel. Dawn's belly was full of butterflies as she peeled off her panties and unhooked her bra. Making sure the curtains were closed, she turned to Maria.

"What's in the box?" she asked.

"Cameras!" Maria said excitedly, opening it and pulling out some apparatus.

"What?" Dawn laughed, watching as her mother quickly attached the small webcams to little metal mounts near where the rear tire of the bike would have been.

"Cameras! I've set it up so we get a split-screen on the television of our butts getting pumped. What do you think?" Maria said, smiling. Dawn just shook her head in disbelief.

"Hot," Dawn said without sarcasm, "Fucking hot. I can't wait to see your little hole gettin' stretched!" Maria laughed, hurriedly pulling off her own sparse clothing.

"God I'm so fucking wet," Maria giggled, touching her smooth pussy. She held up her glistening fingers with a giggle. "Here, bend over babe. I'll lube you up."

"Alright. Then I'll do you," Dawn said, bending over on the arm of the couch, her knees straight and her big juicy bum stuck high in the air. She felt her mother's hand part her thick buttocks, and the cool kiss of a huge dollop of lube. "Whoa, ya think that's enough?" Dawn laughed, her little pucker flinching at the cold.

"We don't want to have to get off halfway through, do we?" Maria said, pouring on another dollop. Dawn squealed and laughed as Maria pushed her finger into her daughter's bum up to the second knuckle, lubing her up inside.

"Or do we?" Dawn giggled. They both laughed as Maria finished lubing up her daughter, then handed the bottle to Dawn and bent over, her hands on her knees. She too flinched as the cool lube kissed her rosebud.

"My, what a cute little pucker you have," Dawn giggled, "I can't believe it could stretch to take anything bigger than a pin!"

"You just wait till you see yours in that camera, girl!" Maria giggled. Lubed sufficiently, Maria bounced over to the dimmer switch and lowered the lights a bit. Their smooth, tanned Latin skin shone like gold in the combination of the soft incandescent light of the bulbs and the flickering orange of the roaring fire in the hearth. Their buttocks glistened with the smeared lube, and positively reflected light where the two soft buns descended into the tight trench between. They both looked apprehensively at Maria's creations, sitting side-by-side, facing the television. The flapping of butterfly wings was almost audible from each belly. Maria bent down and flipped a small switch on her video apparatus, and a perfect view of the underside of the bicycle seat, looking up through the hole, flickered onto the screen. She smiled over at her beautiful nude daughter, already breathing heavily, nerves overtaking her.

"Ready?" Maria asked, biting her lip. Dawn nodded, trance-like, then broke into a wide, sparkling, excited grin. They both climbed onto the bikes, their wet pussies smearing on the seats, then watched each other's little rosebuds come into view, perfectly centered for the camera over the hole in the seat. In the bottom of the view, they could just see the tip of the long dildo on each of their bikes, resting at its retracted setting. Maria had affixed a stiffened silicone rubber model to each mount, bright translucent pink, complete with veins, balls, and a bulbous head. She had figured it would be best to practice with something akin to a real penis. Strong as a tree trunk, but still soft to the touch, they were perfect.

"Oh my GOD!" Dawn squeaked, looking at her own little hole in the camera, "Are you sure anything's going to be able to fit inside of me?" Maria laughed.

"You'll be surprised how much you stretch," she said, looking over the little dials she had mounted on her handlebars, "Have you ever played with your ass before?"

Dawn blushed a bit. "Well, I've used a soapy finger in the shower before while I was getting off, and I tried one of my little vibes in that hole, but only got in a couple inches before I got scared. That was before I talked to you."

"You naughty girl," Maria said wantonly, making sarcastic kissy lips at her and winking, "Well in that case, you should probably start it out really low and work your way up."

"Alright," Dawn said, moving the dial to two inches, the lowest setting.

"Now remember," Maria said, arching her back and sitting up straight, pressing her booty down tight on the seat for the camera, "The biggest thing is to relax. If you clench up tight, especially when it's deep inside you, it's going to hurt. If you have problems stretching to accommodate the girth of it, use the muscles in your bum to push out just a tiny bit. That will open you up, and it'll just slip right inside." Dawn grinned.

"This from the girl who nearly 'brought the house down' screaming when this was last done to her?" she giggled. Maria blushed.

"Well, take the advice anyway, smartass," she said, smacking her daughter lightly on her juicy rump, "I've been around longer than you."

"Alright, alright," Dawn giggled, "So how do these things work?"

"OK, for the regular 'fuck mode' [Dawn giggled excitedly], you press this button here. That'll release a catch..." Maria explained. They both pressed the button on the handlebars. There was a soft, well-oiled clicking sound, followed by a hiss of escaping fluid pressure in the ram. "Now remember to relax, and push out just a little with your muscles," Maria said quickly, taking a deep breath as she said this.

"Oo!" Dawn squeaked. She obeyed her mother's suggestions, and jumped at the electrifying sensation of the tip of the dildo popping past her sphincter. Her tight muscles settled around the ridge of the dildo's head, flexing comfortably.

"How's that?" Maria said with a smile. They looked up at the screen, both breathing hard at the sudden, even if slight, penetration of their private holes. Both their anuses stretched tightly around the tips of their respective dildos, flexing with excitement.

"God that looks so fucking hot," Dawn gasped, shaking her head.

"How does it feel?" Maria asked, shifting her butt on the seat to get comfortable.

"A bit of a stretch," Dawn admitted uncomfortably, "But I think I just need to concentrate on relaxing."

"Breath deeply," Maria reminded her. Dawn began slow, deep breathes, her heavy breasts heaving. "Alright then," Maria said with finality, "Whenever you're ready, babe. We'll start together."

"What setting are you starting at?" Dawn asked her mother. Maria looked down at her dial.

"It's goes up to ten inches, but I'm starting myself out at five," she answered.

"Ooo, five inches of cock in the ass, huh? Feeling ambitious?" Dawn giggled.

"Why, what are you starting out on?" Maria blushed.

"Just two."

"Two inches?" Maria said with mock incredulity, "Any daughter of mine can take more than two inches of dick in her tush, even if it is the first time. I didn't give you that big beautiful bum for nothing, babe. Crank that sucker up!"

"OK, OK!" Dawn giggled, turning the dial up to five inches, "There, now we're even. Happy?"

"Mmm, yes, but I'll be even happier when I see the look on your face after you've taken those inches," Maria said devilishly. Dawn stuck her tongue out at her and giggled.

"Ready?" Dawn said.

"Ready."

At the same time, both girls began to pedal slowly. The mechanisms below forgotten, they watched each other's screen, transfixed by the clear, sexy image of their butts getting penetrated for real, each for the first time in 18 years. Gradually and gently, they watched the shafts begin to slip silently up their tight butts.

"Oh my God..." Maria muttered, closing her eyes and breathing deeply.

"Oh my GOD," Dawn echoed, groaning deeply as the inches slid into the uncharted territory of her tight, teenage rectum, "Wow!" Dawn gasped, lost for words.

"Nnnggg!" Maria groaned piteously, her own dildo finishing its five-inch journey and beginning to withdraw. Dawn's followed suit. Both girls were already breathing hard. Dawn flinched and whimpered as she involuntarily clenched her bum when the dildo was deepest inside of her. "Just breath, baby," Maria said, half to herself and half to her daughter. Dawn nodded, watching her mother's screen as Maria's dildo stopped with the head just inside her tight hole, then began to plunge back into her bowels.

"God I love it!" Dawn moaned, relishing the full, stuffed feeling, twinged with a tiny bit of aching pain, as the dildo slid in to its full five inches again.

"So do I!" Maria gasped, "All these years I had no [unng!] idea!"

"Do I have to stop before I can adjust the depth dial?" Dawn asked breathlessly, pedaling faster. Maria shook her head, leaning over her handlebars as she pedaled faster herself.

"No. Think you can take another inch?" She said, smiling over at her daughter, her face and heavy, swinging breasts glistening with sweat.

"Can you?" Dawn said with a wicked smile. They simultaneously cranked the dial up to six inches, just as the dildo was beginning its in-stroke.

"Poooeewww!" Maria gasped, the breath driven from her as the dildo slid into her ass an extra inch.

"Uhhhhnnn!" Dawn groaned beside her, and began breathing deeply again.

"Too deep for ya?" Maria taunted, watching her daughter's anus clench around the invader on the screen.

"Not nearly! Just need to keep breathing, that's [awwwhhh!] all!" Dawn gasped, her breasts heaving as she sat straight up on the seat of the bike, pedaling at a steady clip. They both watched the split television screen as they pedaled, the dildos sliding soundlessly in and out of their butts. They had come off synchronization, and as Maria's dildo was withdrawing, Dawn's was sliding inside. In and out, in and out the dildos went, plunging up and down in the moaning, groaning girls' bottoms. Their tight, unused little holes gripped the pink veined shaft tightly, getting pulled in and out slightly with the merciless machines' thrusts. Next door, their pussies positively drooled, gleaming pearls of their sweet juices clinging to the lips of their jealous holes.

With a challenging look over at her daughter, Maria cranked the dial up to seven inches. Dawn, her eyes wide with excitement, smiled broadly and turned up her dial as well.

"Ooooo fuck!" Maria groaned, gritting her teeth. Dawn watched her mother's tight hole clench hard on the shaft just as it was deepest inside of her.

"Relax, Mom," Dawn cautioned, breathing deeply as the full seven inches welled up in the bottom of her belly. She kept her bowels slack, letting the machine do its work, and took the length easily. "Sit up straighter," She suggested. Maria complied, her breasts bouncing heavily as she pedaled, her chest heaving with her deep, cleansing breaths. Dawn took her eyes off the screen for a moment and looked over at her mother, where the dildo was sliding up and down underneath the seat. It was almost just as tantalizing to not be able to see the action and simply know exactly what was happened at the other end of the dildo. Maria gasped and groaned again as the dildo went deep up her butt. Dawn felt her insides being tossed out of the way of the gleaming pink shaft as it speared up into her rectum.

"Mmmmm fuckthat'sdeep!" Dawn groaned, taking a hand off the handlebars and pressing on her abdomen to calm her innards.

"Seven inches all that big butt of your's can [nnnnnnggg!] handle?" Maria gasped. Sweat poured off their bodies, running down their shining backs and over their quivering buttocks, divided now by the thick dildo that plunged in and out between them.

"You wouldn't [oooohhhh!] dare!" Dawn gasped back, her eyes widening as she watched her mother crank the dial up to a full eight inches. Not to be outdone, Dawn followed suit.

"Let's slow it down," she suggested, breathing hard. They slowed their pedaling to a crawl, their dildos now synchronized. They watched each others' invaders on-screen as they pulled out until only the head remained within them, then slowly began to slide back up their butts.

"There it goes!" Maria groaned, sitting up straight and breathing deeply. She looked sideways at her daughter. Dawn was watching her mother's screen intently, a smile on her lips. Sweat glistened on every inch of her body and beaded off her brow and petite nose. Maria looked down at the dildo underneath her daughter's seat, slowly disappearing up into her booty on its way to that coveted eighth inch. She looked back up at the screen to see Dawn's anus stretch around the dildo, flexing slightly as her daughter fought to control her spasming muscles.

Dawn closed her eyes and let loose a slow, breathy whistle, marveling at the sensations coursing through her posterior, sensations she never thought could have existed. She relished the feeling of the hard, yet soft, slick shaft, slowly sliding up between her slippery, sweaty buns, disappearing up into her most private hole and deep into the heat of her body. She could feel each and every one of the smooth veins in the shaft, and even the ridge of the head, pushing inside of her, deeper into her rectum than ever before. As the dildo passed the seven-inch mark, a dull, heavy, aching pain swept through her body from her anus to her throat.

"Uuuuunnnggghhh!" Dawn groaned, her brow furrowing and her hand quickly going to her belly. Next to her Maria's mind was calling back the night she lost her anal virginity to Dawn's father, remembering the feel of his hot cock up inside her tight, teenage bum. Him grunting with pleasure, she with pain. For some reason, she now found the image incredibly exciting, imagining her face contorted as he plowed her ass, and imagining what he saw as he looked down at her hips as they bounced against his. The image was suddenly swept from her mind as two things happened: first, she felt the dildo pass that seventh inch. And just a split second later, as though Dawn was feeling exactly what she was, Maria heard her daughter let out a long, painful groan.