Autumn and Marty

I have no idea what possessed me to write this story but if you like it, or have any advice, comments are greatly appreciated.

All characters are 18 or over.

*****

Marty stared down into the vial of faintly glowing green liquid. He was certain he had finally perfected it. The first time he had used the love potion, almost 4 years ago, he had begun a chain reaction that destroyed his old world. He had sworn off using any of his grandfather's (Ricky's) destructive inventions for love or sex but now he was getting desperate.

Ricky had left the family, once again, without any real explanation - simply stating that he would return and warning his grandkids not to mess with his stuff while he was gone. It had been 3 months since Ricky had vanished through one of his portals and Marty's lust and boredom had finally got the better of him.

Since the first catastrophe with the love potion which turned the worlds inhabitants into freakish monsters, Ricky had discovered the error in his calculations and had spoken at length on where it had gone wrong. Marty hadn't paid much attention to his grandfather's ramblings at the time but now that several years had passed, and he was no closer to seducing the love of his life - Vanessa -Marty had decided to try it again.

In the 6 years he had been going on wild adventures with his genius, unstable grandfather, Marty felt he had picked up quite a lot of knowledge surrounding Ricky's ridiculous inventions.

He knew he would never be able to compete with his grandfather's godlike intellect but when he found the revised love potion recipe stashed away in the garage (amongst dozens of other insane blueprints and equations) Marty had been confident he could piece it together.

Now, 2 weeks since finding the potions recipe, Marty found himself with one, small vial of the luminous green liquid, and a perfect plan to use it.

***

Autumn had finally had enough. She was tired of getting ignored, of big-titted bimbos getting all of the attention and stealing her boyfriends.

Autumn had thought going to college would be fun, that there would be constant parties and she would get laid whenever she wanted. But instead it was disappointment after disappointment. Every guy who did show her a little attention would always end up losing interest and going off with another girl, and Autumn knew why.

No it wasn't because she was arrogant or selfish, or was too picky when it came to men (all things Marty liked to point out when Autumn was annoying him). Autumn knew the reason she wasn't getting lucky was because of her flat chest.

She blamed her mother, Steph, for this of course. B

Steph may have bigger breasts than her daughter but not by much and Autumn blamed these genetics on her lack of success. Fortunately, Autumn had an easy fix for her problem, a solution that had backfired terribly when she tried it several years ago but one which she was now confident she had perfect control over.

When she had first noticed boys weren't paying enough attention to her due to her smaller than average tits, Autumn had the brilliant idea to use one of her grandfather's incredible inventions - the Morphizer-EX.

The Morphizer-EX was Autumn's favourite invention of Ricky's. It was a simple machine with a few dials and a lazer which could be set to change the size and molecular makeup of just about anything.

For example, a bit of dirt could be turned into a diamond, which could then be enlarged to the size of a house. However, Autumn had no such plans. She just wanted massive tits.

The last time Autumn had used the Morphizer-EX she had quickly lost control when stood in front of the machines lazer. Instead of simply making her breasts larger, Autumn had turned herself into a freakish giant, trapping herself inside her parents garage (which doubled as Ricky's laboratory). The situation then escalated, as it inevitably always does, leaving Autumn more than a little traumatised. However, it had been almost 4 years since that terrible day and Autumn was ready to try it again.

She entered the family garage and flicked on the light. The fluorescent lighting buzzed and blinked into life as she scanned the dirty, cluttered room for her goal. She spotted it quickly, loosely covered by a tarp in the opposite corner. Autumn placed her mug of black coffee on one of the shelves before removing the tarp and wheeling the contraption into the centre of the room. Autumn hated the taste of coffee but she needed a burst of energy and a pot had already been brewed in the kitchen.

She quickly plugged the Morphizer-EX in and set the dials to the necessary settings. Autumn then set up the screen that the lazer would be pointing at - a screen made of a special material that would absorb the lazer beam whilst remaining uneffected - one of Ricky's clever safeguards to try and keep the laser under control.

Autumn switched on the lazer and watched as it fired a steady, yellow beam into the protective screen. She took a couple of deep breaths before moving onto the next step. In one smooth motion Autumn reached into her tank top and whipped out her plain, white bra.

She looked at the flimsy material and pulled a face at its measly size. What better way to test the Morphizer than by using one of her bra's, she figured she would need a bigger pair anyway to match her breasts - if everything went to plan.

Gingerly, Autumn dangled the right cup over the lazer and slowly, carefully, lowered it into the ominous, yellow beam. Instantly, as soon as the light came into contact with the white cotton, the right half of the bra began to balloon ridiculously, inflating 5 cup sizes in seconds. Autumn laughed in excitement as she adjusted the bra and moved the left cup into the beam. The same effect took place and soon Autumn was holding one, massive bra that could comfortably cradle two ripe watermelons.

Pleased with the results, Autumn tossed the bra aside and removed her tank top, leaving her naked from the waist up. She then adjusted the power cable to the Morphizer-EX so that in the all too likely event that history should repeat itself, Autumn could kick out the plug and cut off the beam.

Now that this was in place Autumn took another deep, steadying breath before edging herself forward into the yellow light. She angled herself so that she was mostly side on with the lazer and could dip in and out of it's effects. Just as her right breast neared the light Autumn stared down at her chest and stated with as much confidence as she could muster:

"Goodbye pancakes, hello melons..."

***

Marty finished applying his favourite cologne and adjusted his best yellow t-shirt in the mirror. He examined his appearance one last time before deciding he was ready to put the rest of his plan into action.

Marty hopped down the stairs and into the kitchen where he heard a familiar buzzing coming from the garage. He walked past the half empty coffee pot he had just boiled and into the adjoining garage. What he saw made him immediately freeze and his mouth drop open.

Standing before him was his older sister, Autumn. But not the usual, ginger, flat chested, ordinary Autumn he had grown up with. This Autumn was naked from the waist up and had tits the size of beach balls.

"W-what the fuck Autumn?" Marty gasped before immediately spotting the Morphizer sitting nearby. "You u-used that...again? After what happened last time? You were turned into a m-monster!"

Autumn was ecstatic with the results. Her tits were absolutely massive and surprisingly symmetrical. She had kicked out the plug the moment she was happy with the size and it had worked brilliantly. Well brilliantly except for the fact that her brother had just stumbled upon her half naked and he was clearly completely rattled. Marty had nearly completely gotten over his stutter in the past couple of years and it was only real shock that would bring it back.

"Listen, Marty, I know the lecture you're gonna give me but it's done now. I figured out how to use it safely and I've pulled it off. I hated my boobs and now they're perfect!"

Marty hesitated and licked his lips. His sister's tits were incredible. He had seen many creatures with massive breasts in his travels but somehow none were as amazing and tantalising as Autumn's. They bounced and swayed slightly with her breathing and Marty was practically hypnotized by them. He did finally draw his eyes away to scan the room and give himself a moment to think and take in what had happened. Except as soon as he pulled his eyes away he noticed something even more shocking.

"Uh, what the hell is that, Autumn?" Marty pointed a finger to the shelves next to the Morphizer and his hand was literally shaking with trepidation.

"What?" Autumn snapped before following where his hand was pointing. She felt an irrational annoyance that her brother had stopped paying attention to her massive tits so quickly, even though his gaze should have grossed her out it actually had excited her. "It's a mug, Marty, you know the thing for tea and coffee. All the shit you've seen with Ricky must have melted your brain if you find that so surprising."

Marty ignored his sister's scathing tone and gulped loudly in an effort to calm his nerves.

"What's in the mug, Autumn?" He croaked through a suddenly tight throat.

"Eh, coffee dumbass," she retorted, putting her hands on her hips.

'Why was this dweeb talking about drinks when I've turned myself into a sex goddess...and why do I care what this little shit thinks?!' Autumn thought but did not say.

"Coffee!?" Marty spluttered. "Coffee! But you don't even like coffee! And you weren't even meant to be here today! You said you were on a date!"

Marty held both hands to his head and was practically hyperventilating. His gaze had turned back to his sister and despite his apparent horror he couldn't help but drop his focus to his sister's incredible breasts as his mind whirled.

"I needed something to perk me up and help me focus. Jake cancelled the date, okay? And I can come here whenever I want - it's both our parent's house!" Despite her defensive tone Autumn was getting unnerved by her brothers obvious dismay.

"You're not the only one who had the bright idea to revisit some of Ricky's old inventions. I found a revised recipe for the love potion I tried years ago. Remember the one? Nearly destroyed your world and did actually ruin mine? Well I made it so it was safe and a little less overpowering and...I was gonna use it today. Vanessa's coming over any second for some joint revision and she's been using coffee to help her focus," Marty sighed and rubbed both his eyes wearily. " Coffee, which I filled with the new and improved love potion..."

It was now Autumn's turn for her mouth to drop open in shock.

"You lectured me on messing with dangerous inventions!? While you're doing exactly the same fucking thing! And coffee, Marty, really? You just left it lying in the kitchen!"

Despite how angry she was becoming she was acutely aware of a wetness forming between her legs. She crossed her arms hotly and was amazed at the weight of the tits spilling over them.

"I only left it for a minute and no one else was meant to be in the house!" Marty continued to address his sister's mammoth mammeries and found it even harder to pull his gaze away.

Despite the raging mix of emotions coursing through him, his cock had ignored what was appropriate and had begun rising to attention. Marty thought a silent prayer for his brilliantly enhanced boxers which, much like the Doctor's TARDIS, had been altered to be larger on the inside. This meant no matter how hard he became he was completely concealed. This rather genius invention had saved him from countless embarrassing occasions.

"It was still completely careless!" Autumn raged, refusing to back down. She noticed that despite her brothers fixed stare at her magnificent new assets he clearly wasn't even getting the smallest of boners and for some reason this seriously bothered her. She felt the almost uncontrollable urge to demand why Marty was not physically responding to her irresistible body. She kept telling herself this was just her pride speaking and she pushed on in the conversation in an effort to distract her dirty thoughts.

"I, eh, thought you said the love potion affected everyone except direct relatives, anyway? Maybe you'll just have to make a new batch and try again at your sad attempt at seducing Vanessa."

Marty sighed and rubbed his eyes once more.

"Yeah, but that was the old formula, Autumn. God knows if that rule still applies!"

"Well I think we're freaking out over nothing," Autumn huffed, moving her hands to her hips and trying not to rub her thighs together. 'Why am I so horny all of a sudden?' Autumn wondered.

"Fine let's forget the potion - which was a nightmare to make by the way! What are you planning on doing with those things," he gestured to the gigantic breasts unnecessarily. "Mom's gonna go crazy when she sees them. She had to help you last time this went wrong, remember?"

Autumn bit her lip anxiously for a moment before answering. She had rushed into using the Morphizer but she had had one idea and now that she had this love potion leverage on him, maybe she could make Marty help her.

"Ricky had that material ages ago. That stuff you could make into bags or pockets or whatever. Which could hold wayyy more than it should have. I want some of that to sew into a bra for the meantime until I'm ready to show these to Mom. And since I've caught you being a little pervert, I want you to tell me where it is. I know you helped Ricky get the materials to make the stuff. Tell me that and I won't mention the potion to Mom."

Marty was finally able to look his sister in the eye and glared at her.

"You're trying to blackmail me into helping you? Fuck you, Autumn," Marty was pleased with the steel he managed to put into his own words.

Suddenly Autumn's stubborn, angry demeanour dissolved and her face turned desperate. She brought her hands up in a literal prayer. For some reason she suddenly couldn't be angry with Marty.

"Please, please help Marty. You're right, Mom will kill me. I need your help. Mom comes home in a few hours and I don't have the first idea how to find this weird material stuff and it's the only plan I've got."

Marty was taken aback by his sister's seemingly genuine desperation and his anger also dissolved.

"I'm sorry Autumn, I want to help but I used the last of that space saving stuff. I built them into a few pairs of boxers to hide my own...secret thing."

Autumn gasped in relief and quickly stepped toward her brother until her tits were almost touching him.

"Oh please, please, please give me your boxers. I could refashion them into a bra. I'm sure you don't need them!"

Then before Marty could even begin to object Autumn dropped to her knees before her younger brother and began yanking his pants and boxers to the floor. She told herself she was only doing it out of desperation for the material but some other, darker thing urged her on.

"A-Autumn! What the fuck? I'm using them!"

However, Marty's objections came far too late and suddenly he was naked from his waist down to his ankles and out sprang his no-longer-concealed member. And out it did spring.

Autumn had just tugged down her brothers boxers to his knees when out popped his restrained cock which sprang up with such force it bumped her chin and slid right up the right side of her face. Even though the hit of his bellend was relatively light, the shock of it sent Autumn tipping back on her plump ass.

"What the fuck is that, Marty?!"

Marty made a strangled, high pitched 'oooh' - a noise he only made when he was extremely stressed, a noise he had avoided making for years.

"I told you I was using the material!" Marty whined.

Autumn gazed in awe at the monster that stood pulsing above her. Her little brother's cock was a rod of meat like a python with a bulbous, angry purple head which gleamed with a pearly drop of precum at it's tip.

"You used the Morphizer-EX too, didn't you?" Autumn whispered, transfixed. She should be furious that her brother chastised her for using Ricky's old technology after he used the Morphizer and the love potion but instead she felt excitement and...hunger.

Marty had closed his eyes in horror when his second secret was revealed so had missed his sister's lustful gaze and nearly jumped out of his skin when one of her slender hands suddenly gripped onto his dick.

"Jeez! What are doing Autumn?"

"I'm just...comparing," Autumn spoke almost robotically as she began squeezing and rubbing her own massive tit with one hand and stroking her thumb under the colossal shaft of her brother's member. Her fingers couldn't quite touch to circle around it's girth.

"Autumn, please, what the f-fuck..."

But his sister ignored him and moved both hands to grip and stroke the length of his cock. The sight of his sister sat beneath his prick with her massive, impossible breasts resting over her knees was the most erotic thing Marty had ever seen, and though his conscience screamed in the back of his head to stop what was happening, Marty stood motionless.

Autumn's hunger grew and her hands began to move faster and more deliberately. She stroked firmly from base to tip, rubbing her thumb up over the massive bellend.

Chills ran up Marty's back and he tilted his head back. He hissed lowly with pleasure which turned to a sharp gasp as his sister's hot wet mouth engulfed the head of his cock. Marty looked back down and groaned as he watched Autumn's mouth bulge obscenely to accommodate his size. It was like a fist pushing into her mouth. Her eyes met his was an intensity that was almost scary.

As if taking the direct eye contact as a challenge Autumn pushed forward and several more inches of Marty's cock slid into her mouth and into her throat.

A small voice in Autumn's head remarked on how weird it was that her mouth and throat could accommodate this insane size without choking her or triggering her gag reflex. For the most part though Autumn was just pleased she could swallow down Marty inch by glorious inch with minimal difficulty.

Marty gawped in awe as his prick pushed and pushed smoothly until his sister's nose was buried in his little bush of pubes at the base of his shaft. He couldn't believe it. He had invested in some other, more subtle, upgrades for his cock he hadn't had the chance to mention to his sister - upgrades which he had intended to use for the first time on Vanessa. Even though he knew his member should fit it was another thing entirely to see it in action and feel his cock fill his sister's entire throat.

Autumn held her face there for a few seconds. Enjoying being filled and basking in the pleasure radiating from her brother. Somehow she could breathe with only minimal difficulty even though the head of this monster cock was practically in her stomach. Eventually though Autumn slid her head back and pulled her mouth free of her brother's python cock with a loud, wet 'pop'.

Autumn's saliva coated Marty's entire length and strands hung from her lips and chin. Before Marty could even begin to make a comment Autumn ducked forward and sucked down her brother's cock again, quicker this time, and began bobbing back and forth. Her pace was fast, rhythmic and slobbery - taking almost the full length every time.

Marty was in heaven as he watched his sister suck him and watched her gigantic tits wobble and bounce. Marty's hands hung motionless by his side until Autumn soundlessly moved them to the back her head. Marty took the hint and grinned with excitement.

Without hesitation he began to push his sister's head deeper onto his cock, then he began thrusting his hips forward gently in time with her bobbing head. When Autumn still didn't gag or attempt to pull away Marty steadily grew bolder and his thrusting became harder until he was powerfully face fucking his sister. Autumn dutifully knelt with her arms by her side and let her brother have his way with her mouth and throat.