Author's Note

More set-up than smut, really. It's the start of a series.

Meditations and Experimentation

Looking back, the whole thing had probably started when Derpy first breastfed her daughter, or anyway when her boobs started gearing up to feed a foal. A bit of swelling seemed normal and expected and besides, she'd only gone up from the low end of average without quite making it to above average for a pegasus mare.

The pregnancy itself had had its ups and downs. The expected minor irritants and inconveniences without any major complications. It had been easy to put up with for Derpy because she had been looking forward to holding her daughter in her arms.

Her friend Berry, pregnant at about the same time, had resented much of the experience, although she'd hid it well and only admitted it to Derpy and probably her therapist.

They shared a house for convenience and so neither of them was technically a single mother. Berry had wanted to move to the heartland, Derpy had picked Ponyville once it was confirmed that their foals were unicorns. Close enough to Cloudsdale for her parents to drop in, close enough to Canterlot just in case the kids wanted to go to one of the fancier schools in the future.

She'd loved her daughter instantly. Nursing Dinky was a perfect moment of intimacy, every time. She'd privately hoped that Berry would experience something similar, but the mare hadn't even been surprised when holding Ruby Pinch left her feeling rather unengaged, and feeding her had apparently been an uncomfortable chore.

Had it perhaps been strange to offer her help with nursing Pinchy? Her friend had bonded with the foals only slowly over a period of months and felt no real compunctions about it, only questioning whether Derpy had enough milk for two. That question had seemed utterly, comically absurd at the time, like asking a grown pegasus whether they could fly. Was that a normal reaction to a question that had probably seemed entirely sensible to Berry? Unicorn foals were ravenous eaters to make up for all the energy wasted on uncontrolled magic surges.

There's enough for everyone.

She'd responded with total conviction that nobody would ever go hungry on her watch. She remembered that moment with clarity, how right it had felt to give voice to that notion.

Nursing two foals at the same time had been delightful. There'd been a little growth, but that had made sense. Supply had to rise in order to meet demand.

It always would.

Still, it'd be dishonest to say that young kids weren't stressful, even though Berry and her made a great team. Derpy benefited a lot from the fact that Berry was a pillar of calm in the face of all the little everyday messes and problems. In any case, the stress of the daily routine was probably to blame for Derpy not noticing sooner.

She'd been sitting on the couch, gently massaging her breasts. She preferred to be topless at home, although she kept a shirt near the door in case of unexpected visits. Berry didn't react either way, and Derpy had taken advantage of the fact that her friend didn't appear to have the emotional range to be invested in the proprieties. Comfy sweatpants were her only concession to something resembling decency.

It was unfailingly relaxing to treat her own breasts with such tenderness, and so she'd been sitting there and contemplating her chest. How full and heavy with potential it was.

Except that thought had given her pause, at the time. She'd stopped nursing the fillies some weeks ago. She'd realized that she should have dried up eventually.

She never would.

These thoughts had felt correct, for lack of a better word, but she hadn't understood why that would be the case. Objectively, it hadn't made much sense, really. Derpy had thought about it further. She'd simply stopped nursing and that was that. And yet, when Berry had stopped nursing, earlier than Derpy, she'd been candid about discomfort as she waited for her breasts to get the message that there was no further demand.

Never full.

That idea had explained why she hadn't had any problems after no longer breastfeeding, but it hadn't made a lick of sense on its own.

She hadn't gotten further than that when Berry came home. Usually the mare dropped herself into her recliner carelessly, this time she lowered herself gingerly, holding a can of beer.

Derpy cocked her head, distracted from her own musings. "Got your ass beat?"

Not getting into fist fights was one of those things Berry had complained about during her pregnancy. Derpy herself had been surprised that even this close to Canterlot Berry could find enough fellow meatheads to regularly fight in a sorta friendly fashion.

Berry snorted. "Nah. Well, kinda. The big red lad from the orchard is slow, but it's like getting hit by a hammer when he gets one in, yeah?" The earth pony shrugged. "Still won. All'a these rubes are amateurs. Kids go to bed alright?"

"For now," Derpy nodded with a smile.

"Good." Berry cracked open her beer and took a sip. "Turns out they serve a nice warm lager down at the Copperhead. Just the right temperature. Can't wait 'til either of the kids got enough magic to fix a drink like that."

Derpy made a grimace. "You disgust me," she claimed without heat.

Berry grinned. "Says the girl who wants to feed the kids fish."

"Protein is important." Not that the earth pony would actually oppose the idea. Berry Punch would eat anything that wouldn't literally poison her rather than go hungry. Food was one of the three things the big mare actually cared about, alongside Derpy and getting into fights. She shook her head. Trying to get Berry to drop that last one had been futile so far. "Speaking of food ... "

"Yeah?"

"Still got milk." There really wasn't anything she couldn't tell Berry, but the lack of embarrassment Derpy felt still surprised her.

"Huh, still?" Her gaze briefly dropped to Derpy's chest. "My sincerest condolences."

"Hah-ha. You're a funny mare, Berry."

"That's why you'll kill me last, yeah?" She chuckled briefly before turning serious. "Well, lay it on me. This is the first time I've seen you be anything less than completely in love with your own tits."

"It's not that bad," Derpy claimed, failing to convince either of them.

"I've seen you lose anywhere from ten to thirty minutes stroking them while I sit here, sipping a drink, Derps. You meditate on them." There was no accusation or amusement in Berry's tone, she was just calmly laying out her observations.

"Very relaxing," Derpy agreed. Did she sound a touch defensive? An outside observer might assume that that had been what she'd been doing before Berry came home.

Berry tapped the side of her head with her knuckles. "I may be missing a few pieces here, but all the equipment still works. If I spent ten minutes tweaking my boobs, relaxed won't be what I'm feeling."

"That's what nipples are for." And anyway, there was a big difference between gently massaging them and really giving her boobs and nipples a workout to get off.

"Fair. You're the expert on your own pair. So talk."

"Expert is right. I know ... feel things. About my breasts." Even now she was idly brushing her fingers across them. It kept her from being nervous about how awkward she sometimes sounded.

Berry just took a sip from her beer while gesturing for Derpy to explain with her free hand.

"I won't run out."

Never.

Her friend shuddered briefly. "Ugh, better you than me, girl. I'm happy to be done with it." She shrugged. "Well, stay hydrated and eat accordingly, yeah?"

"No, I mean -" Derpy sighed, stood up and jerked her head in the vague direction of the hallway and bathroom.

Berry stood without complaint and followed Derpy. Normally she enjoyed watching Berry move. The earth pony never wasted motion or hesitated, every movement economical and precise, with a grace at odds with the fact that Berry would have been uncommonly tall even as a stallion and sported the build of a big, chunky bruiser.

In the bathroom, Berry just sort of stayed leaning in the frame, sporting an expression of detached curiosity. Derpy felt like she was about to cross a boundary, but having someone watch and understand seemed like such a good idea that she forged ahead anyway.

She faced the tub, wondering if perhaps she noticed new things because she wasn't preoccupied with a foal or two in her arms. Cupping her breasts, she realized she wouldn't even have to touch her nipples to call up the milk. Soon enough it formed droplets on the tips.

"Look mom, no hands." Berry tipped her head back and upended the can to empty it out after her comment.

Derpy didn't deign to respond. She was rather distracted by the sensation of her milk streaming down the undersides of her breasts. A pleasant new experience.

Berry set down the can and crossed her arms. "You'd let me know if this was some really bizarre come-on, right?" She tilted her head. "I'm not real good at just, uh, inferin' that sort of thing."

Derpy held up a hand, their signal to indicate that she was taking a moment to get her thoughts and, more crucially, the words in line. Berry waited patiently, as ever.

"Full disclosure. I have been crushing on you? You're very attractive to me, I mean. But no, that's not what I'm doing right now."

Berry Punch was probably not conventionally attractive. Her muzzle was ever so slightly crooked, the cost of doing business, the mare would say. She had the seemingly standard wide earth pony hips, but her broad shoulders and thick waist had given her a blocky look when they'd first met. Someone unkindly inclined could have called it masculine, and Berry had been fairly modestly endowed on top. Perhaps even counting as below average for earth ponies. Derpy had to admit that she paid very little attention to breasts that weren't her own. The size of another pony's rack was just information to her, it had no emotional significance.

The earth pony had always been hard as steel and still kept up her strength training, but the sedentary lifestyle and uninterrupted access to good food in Ponyville meant that the mare had developed a layer of padding, giving her a softer look even as it had increased her apparent bulk. She was extraordinarily comfortable to lean against and doze for a while, Derpy and the two foals were in full agreement on that front. She'd always cherish the memories of cuddling against the bigger mare while feeding their daughters.

At the same time, in Derpy's subjective opinion, the combination of highly developed muscles and a layer of fat had done extraordinary things for Berry's ass.

Derpy would have brought up the topic of sex eventually, the kids had pretty reliably slept through the night for some time now and the worst that would happen was that Berry would go 'Nah, I'm not into it' or something to that effect. If it came to that, Derpy didn't doubt that she could find her own fun locally, or anyway within convenient flight range whenever she wanted something more than masturbation.

Those were considerations for later, however. "Just keep watching."

To avoid making any more of a mess, she'd have to put a little more force into things, and her breasts complied eagerly. Milk arced into the tub in thin streams. Derpy knew that Berry wouldn't be particularly into the display, yet still, just knowing she had an audience got her more excited than the act itself – something Derpy only now learned about herself.

"Huh. Didn't expect that." Berry spent a few seconds just watching. "We can talk about that later. You about done?"

She really wasn't. The pleasant fullness behind her nipples was unchanged. Derpy did regret the whole bathtub idea though. Even if her milk wouldn't run out, at her size, throughput was limited and the milk pooling at the bottom looked lost and pathetic. It would have been a better idea to demonstrate by filling a couple bottles consecutively.

Strange thing to think about, either way.

"Don't feel any different," Derpy eventually stated. She grazed her thumbs along her breasts towards her aureola, which felt very nice, but it didn't arouse her the way the realization that her potential hadn't lessened at all did. She shifted her weight awkwardly.

Berry again seemed to have an idea what Derpy had been thinking as she contemplated the milk splashing against and running down the side of the tub. "That the best you can do? You're just havin' fun, no worries that a kid might choke 'cause you let down too hard."

Derpy drew in a sharp breath as she felt herself grow moist. Up until then she might have been able to conclude the demonstration and simmer down again, but now she expected that she'd have to bring herself to climax or go to bed feeling unsatisfied. She felt as though Berry's words had torn down an inhibition she hadn't even been consciously aware of. Had that still been at the back of her mind, even though she was no longer nursing the kids? It wasn't like she'd ever had a problem like Berry described. Her tits were very accommodating that way. And still, it seemed so obvious, now. She could do so much more.

She gave her breasts a fierce grope while directing an unspoken command for more milk at her chest. Long lances of white liquid splashed against the wall above the tub, projected with enough force that the impact was nearly of a height with Derpy's nipples. There was no end to it, just a constant sense of relief that would never get old. Sooner or later she might climax from that alone.

"So you can keep this up as long as you want?" Berry sounded interested rather than incredulous.

Derpy just nodded, biting her lip. It just felt so good to get all that milk out.

Except ... except she knew she hadn't made a dent in her reserves. There'd always be more milk, waiting for her to call on it.

They'll never let me down.

She gave her breasts another appreciative rub as she continued to dispense milk. "There's nothing I don't love about them." They were beautiful mysteries, as though they had lives of their own. Who knew why they were so gifted? What great things would they accomplish?

Berry seemed amused. "You can stop, right?"

"Yes," Derpy admitted, perhaps a little grudgingly. It didn't even take any particular effort, and as it turned out, her breasts rewarded her even for this. As she stopped expelling milk, she was hit with a brief moment of overwhelming, beautiful pressure. The instant passed and she was left with the usual feeling of pleasant fullness she'd practically stopped noticing. She thought she could feel her glands humming along productively. Had it been reward or enticement, to be made aware of growing oceans of nourishment, only held back by her humble breasts?

She wondered why she hadn't noticed such things earlier. Had she been so preoccupied with her family? Sure, she'd taken breaks to combat stress, but how long had it been since she truly listened to her body? Had all this been waiting for her since the first time her foal had latched on to her?

"Uh, you okay there, Derps?" There was a touching note of genuine concern in Berry's question.

She realized she'd been panting. Her heart was racing. "Yeah. Fine. Great!"

It was probably time to clean herself up and rinse out the tub. Her pants would need a wash due to the milk which initially ran down her chest.

"Well, I guess I'm happy for your tit epiphany." Berry shrugged. "Seems damn useful besides. If we ever get lost in the woods we're not stuck eating grass and leaves. All the wilderness survival I know applies to cold climates."

The climax hit Derpy like a bolt from the blue. She was largely unprepared for the great majority of the pleasure originating from her breasts. Her nerves fired spasmodically, her knees buckled and she had to hold onto the edge of the tub with two trembling arms to keep from collapsing in a heap. A long, low moan tore free from her throat. Past efforts at pleasuring herself seemed entirely incompetent by comparison, and Dinky's sire didn't look much better in hindsight.

"Bloody hell, girl. That's what gets you off? I already made a 'no hands' joke." Berry huffed. "I didn't say that for your sake."

Derpy believed it. She was pretty sure that if Berry had any erotic impulses, they could only be found by ponies in lab coats with very precise instruments, but the fact that her friend viewed Derpy's breasts in a largely utilitarian light didn't do anything to diminish the pleasure caused by the idea of supporting and nourishing another life, especially in the face of hardship and deprivation.

Berry approached and reached out a steadying hand. Derpy found herself glad that Berry remained so unflappable. The night had so far been wonderful and weird, but Derpy wasn't sure she could have enjoyed herself quite the same way if she hadn't known that someone in her life was utterly solid, loyal and dependable.

"You'll never go hungry again," Derpy eventually stated with conviction.

Berry embraced Derpy from behind, interlacing her fingers in front of the smaller pony's stomach. "Thanks, Derps. How you feeling now?"

She eyed her chest briefly. "Full. Not in a bad way. Just full. And I'll keep getting fuller." Derpy realized something else and gestured loosely towards the tub. "Already replaced. Drop in the bucket. If only you could know," she concluded mournfully.

Berry chuckled warmly. "Well, I'd just be stupid if I thought anything would make sense tonight. Is that your thing now? Feeding folks?" Her voice lowered to whisper. "You think the boss would rehire us? Really reduce overhead on the caravans if we didn't need to bring food along."

Derpy couldn't help but squirm against her taller friend as she imagined those months-long trips to remote trading posts, draftponies and guards alike depending on her to keep them fed and healthy. "D-don't tease me," she all but moaned.

"'kay." Berry released Derpy, gave her a firm pat on the shoulder and turned to prepare a damp washcloth, something which probably was an automatic response to a perceived mess now that they were cooperatively raising two small fillies.

"The kids been really growin' on me now that they're starting to show some personality," the earth pony commented idly, as though that wasn't far better news than anything to do with Derpy's chest.

Still, the good news definitely added to how great a day it had turned out to be. "That's great!" Derpy hadn't really doubted it would happen eventually, although what Berry so charitably called personality seemed to her more like a phase of tantrums. And despite the long time it had taken for Berry to start forming emotional ties to the kids, she had been very specifically sure that emotional neglect was very bad for foals and had been carefully attentive to their daughters.

Apparently on a whim, Berry decided to squat and reach into the tub with her free hand, dipping a finger into milk before sticking it into her mouth.

Derpy gasped sharply, not from renewed arousal, but from the most incredible feeling of connection to her friend. Casually shared facts and unguarded comments clicked together with perfect clarity. Berry needed her, not for food or shelter, but for the emotional support she'd been denied during all the most crucial stages of her development. The fact that Berry was in the habit of discussing her feelings openly and candidly with Derpy suddenly seemed like the most amazing gift of trust.

She'd probably had similar feelings when she first nursed the foals, although it had seemed very natural to feel closeness and protectiveness towards them.

She threw her arms around Berry for a hug just as the other mare stood again.

"We still not done for tonight, then?" Apparently Berry hadn't experienced a beautiful moment of spiritual togetherness. It probably had just been milk to her.

"We belong to each other," Derpy declared with a fierceness she found surprising herself.

Berry glanced down at the tub again and quirked a brow. "I assume this isn't you asking to date. Take your time and explain," she added, her tone turning gentle.

"It's this feeling," Derpy licked her lips. "It's not about, about sex or romance." Words failed her momentarily. Everything she could think of seemed merely like a trite reaffirmation of their long friendship. None of it had the proper weight to it.

Berry hummed, patting Derpy on the back. "No rush. We got all night or until one of the kids wakes up."

"I feel it in my boobs," Derpy blurted out, blushing.

Berry paused before running her palm over her face with a sigh. "No, really, you coulda taken more time to come up with something less weird. Others got gut feelings, you got boob feelings now?"

Derpy shrugged helplessly, saying nothing to refute the notion.

"Okay, cool. Sorry, I don't wanna make fun of you, and this is definitely not silly or anything." Berry was clearly trying not to giggle now. "Anyway. You're the best friend I ever had, and this friendship has been incredibly healthy for me. You already left a mark on me that's gonna stick even if we started hating each other's guts tomorrow! I don't think this magic nonsense could add to that."

Without waiting for an answer, Berry pushed the two of them apart, resting her hands on Derpy's shoulders. "Uh, you sure that's all you're feeling? Cause I'm thinking you're getting bigger."

Derpy's eyes grew wide as she looked down at herself. At this point, she wasn't as surprised as she might have been before today. As though reacting to her attention, a shiver of delight radiated outwards from her chest through her body. The growth was slow yet observable and deeply satisfying.

She graced Berry with a brief smile, likely a pretty self-satisfied one, then closed her eyes and cupped her breasts. No distractions. As her breastflesh crept outwards, Derpy listened.

She knew the new flesh was dense with glandular tissue, immediately joining in with the ongoing frenzy of production. Even as she felt her nipples expand slightly to match the rest of her breasts, Derpy became utterly certain that her nubs would never really dispense enough milk to outpace her production and threaten her reserves. She wondered where all that milk went while she wasn't calling on it.

Apparently called forth by her unspoken question, the pressure of nearly two years of unspent milk seemed to settle on her for a brief moment. Yet she didn't feel threatened or overwhelmed, but anchored by that weight of potential.

There'll always be more.

The actual result of her growth seemed at first more modest than the experience itself. D-cup, perhaps? Bigger than Berry, now, but nothing life-changing. She hadn't worn a bra in ages, although perhaps not needing one was part of her breast powers.

Derpy had thought it to be over when a raging fire of sheer lust exploded within her. Shaken, she all but fell against the taller earth pony in front of her. "H-Hold me."

Being pulled into a tight hug by her friend, Derpy was free to feel her body. Her tits pulsed larger still, and she silently cheered them on. Milk started flowing and she didn't bother to hold it back. She smiled when her friend's only response was a disapproving click of the tongue.

She'll always be there for me.

She felt a twinge and the peculiar sensation of growth all around her lower body, yet her pants didn't seem to be growing appreciably tighter. Was the change just too small, or had that feeling just been an enticing promise for the future? It was so easy, so pleasant to image herself with hips wide enough to put the most matronly earth pony to shame, a big, wobbling ass begging to be squeezed by Berry Punch's strong hands, and thick thighs holding up a body which wasn't just beautiful but awe-inspiring.

Derpy convulsed in the throes of another climax. Afterwards, she still felt incredible. She imagined herself nearly bursting with vitality, just aching to be shared through her milk.

She very nearly cried with happiness. Her body had become a miracle of pleasure and endless abundance, she had her best friend at her side, and their daughters were a joy to raise. "I feel like the luckiest pony in the world when you hold me."

"Hm." Berry was not very good at accepting compliments of the emotional sort. "Mind putting a cork in it?"

The flow of Derpy's milk slowed to a stop with a mere thought as she took a step back from Berry's embrace. She'd made a bit of a mess of their clothing and the floor, but instead of annoyance, thinking about the clean-up left her giddy. After all, it was another reminder of how much she had to share. Already, her bounty was nearly too much to contain.

Berry shook her head. "Damn, look at those jugs."

Derpy's boobs had grown very large. She'd never had occasion to guess at that sort of cup size. F, perhaps? G, even? They were the sort of rack one might, might, find on a particularly voluptuous earth pony. On a pegasus of her built they looked beautifully obscene. Derpy cupped them to give them a little bounce. Their heft and ponderous wobble was already thrilling, but she could go for more.

"There was some swelling when I started nursing Dinky and then later again with Pinchy but nothing quite like this," she observed. Almost without conscious control, her hands moved to tweak her nipples, which seemed to have grown larger, relatively, compared to the rest of her. They were easily as big around as her thumb, with aereola to match. They grew errect under her fingers, and the realization that they'd be all but impossible to hide got her horny all over again.

"I'm a big girl," Berry commented with a grin. "I eat a lot more than those two taken together." More seriously she theorized, "or maybe they just work better now that you're really paying attention?"

"That makes a difference," Derpy agreed. But the explanation felt lacking. "It's because it was you." She knew, through some strange breast instinct, that their long and close friendship and her budding love for Berry had made this instance of growth special. Grander than what she would get from feeding others.

"Heh. So how big would you like to go?"

Her hands were halfway to her chest in order to mime some appealing size before Derpy slowed down with a frown. She couldn't actually envision a size she could call more than a decent intermediary effort. "Uh ..." She looked down at her chest, hoping for an insight, but apparently her boob feelings had nothing to say on 'how big is big enough'. Derpy suspected that was telling. She dropped her hands and shrugged lamely.

"Hmm." Berry smiled slyly, stepping closer and around Derpy to take up position behind her, turning her back to the tub. The taller mare leaned in and spoke quietly. "Maybe 'big' is just a boring word?"

Derpy suspected that as she was discovering awesome things about her breasts, so was Berry discovering that she liked to tease. She leaned back, which didn't budge the earth pony in the slightest.

Berry reached around and cupped her hands in the air in front of Derpy before slowly extending her arms out. "Maybe huge? Or giant? D'ya want giant tits, Derpy?" Berry proceeded to spread her arms outwards, suggesting an immense width as well as length. An impossible size, clearly.

And yet Derpy felt her breasts throb as though in eager anticipation. Some boring but diminishing part of her had perhaps not wanted to dream of breasts any larger than what she'd just grown. Very unusual for a pegasus, but just big boobs. Now her breath hitched and she squirmed in response to mounting arousal.

"You do, huh?" Berry observed warmly. "Thought I had you all mapped out, but we're both learning about you today, yeah? You gonna dream about havin' to maneuver through doors one massive jug at a time? Or just force yourself through to feel how big you are?"

Even though getting herself stuck in a doorway and then having to unjam herself with brute force should have sounded uncomfortable, even painful, the idea just made Derpy wetter. If she were that big, she'd never want to stop being reminded of it. Constantly working around a pair of enormous tits sounded confusingly enticing rather than inconvenient. "I ... Berry, we got kids to raise!"

"So take it slow." She felt Berry shrug. "You don't even know how far this'll go. I'll take up some of the slack around the house if that's a problem." She paused. "Even if you get that far, it'll seem normal to the girls. I'd like that for them, you know? Growing up totally certain that even if the world ends they wouldn't go hungry around you."

I could feed so many.

Derpy felt the milk churn within her breasts as her nipples stiffened. "Mhmm." Another perplexingly pleasant idea. Still, she would pretty much have to take it slow, besides, getting other ponies to drink her milk would be a task in and of itself. "Don't know anyone else I could show. Who'd want to try a taste." She shrugged, probably seeming more disappointed than she'd intended.

"Might be a slow start," Berry conceded. "Gotta take the long view on getting the town used to you. First you might be 'that busty pegasus', maybe later that poor mare with the milk problem."

"It's not a problem!" Derpy contested with surprising force.

"Slow down," Berry chuckled. "Bet you could get away with all sorts of fun if they think it is. Maybe you can't help running around with soaked tops all the time, reminding everyone of what you got. Maybe sometimes you just got a surge and make a bit of a mess, hm?"

She tried not to giggle, but she so badly wanted ponies to know about her milk, so Berry's idea was particularly entertaining. "Fine, then. Sorry to interrupt."

"No worries. Just imagine, in ten, fifteen years you might be the big-titted town mascot, not like this place has anything going for it but bein' close to Canterlot. Maybe they'll roll their eyes, but just imagine, maybe some weather team blunder ruins the local harvest. No surplus to sell, might even have to buy extra food, doubt many of these rubes're sitting on a spare pile of bits ... except, thank Celestia we got Derpy. Whole town'll get through the winter without going broke keeping themselves fed."

Anticipating the climax in no way diminished it. Her breasts, once more the origin of the breathtaking pleasure she was experiencing, again erupted with milk, forceful spurts splashing against the wall with the frantic rhythm of her racing pulse. Suddenly it was easy to imagine herself with a pair of enormous milk factories, gushing endless streams of milk. She vaguely felt Berry wrap an arm around her waist to steady her, immediately wondering what it'd be like to trap that arm between her stomach and vast masses of titflesh.

"Berry ... Berry, please touch them."

"A'ight."

The bigger mare's hands were rough, but Derpy wouldn't know that by how lightly Berry cupped one of her boobs with her free hand. Even that light touch felt heavenly. It wasn't what Derpy was after, however. She reached up to grab her own tits, placing one hand on top of Berry's and forcefully pushed against her chest. As though provoked by the temporary outside pressure, her production kicked up a notch, milk now spraying from her in two continuous streams. She came again, lightheaded from ecstasy.

"So I take it you would wanna get that huge eventually," Berry stated the obvious.

It was so easy now to imagine herself obscenely, absurdly large, impossible to ignore. No end to her milk, not to force it on ponies but to give them peace of mind that hunger never again needed to be a concern. And still, there was no part of her mind which could look at that mental image and honestly think that it'd be a good final size.

"B-bigger than, than that," she stammered. "H-help me?"

"I'm your mare, Derps. Always will be." Her Berry assured her, voice steady, but seeming slightly amused. "Love what I can do to ya by talking. So I'd like you to listen real careful now, yeah?"

Derpy nodded shakily. With the one hand she wasn't using to clamp Berry's hand to her boob, she started to tug and pull towards her other nipple to ensure the spray of milk continued. It was unclear to her if it was necessary, she could probably just will her boobs to keep it up. The realization that she still felt pleasantly full, the bizarre sense that she was actually more full than before, got her on edge all over again.

"Stop worrying about what's enough. You only just started ... whatever this is. Dream big. Big as houses if that notion gets you going."

Involuntarily, Derpy gasped.

A pair of breasts so vast that the rest of her was little more than a dangling accessory meant to experience pleasure. A cloud platform just for herself to move about freely and ensure ponies could view her from miles away. Nipples bigger than her head endlessly geysering milk so high into the sky, it affected the whole weather system.

Her whole body seemed to quiver. Senseless with pleasure, she pleaded for more, her nipples twitching before unleashing veritable torrents compared to what she'd been doing earlier. The white fluid splashed off the opposite wall. She was disgorging milk forcefully enough that it started to sting her nipples, barely noticeable against the pleasure building unstoppably towards a climax. Derpy groped herself with wild abandon, significantly increasing the spread of errant spurts of milk.

A final pinch of her recently enlarged buds and Derpy's would have collapsed into a heap if it hadn't been for Berry's support. A moan every bit as sloppy as her gushing orgasm and the careless spray of her milk concluded the experience.

Her boobs were so eager to provide pleasure, how had she not noticed before? Maybe Berry's earlier comment that they worked better now that she was paying attention to them applied. "Hng ... Not fit to wear tops anymore. So sensitive. M-maybe they'll simmer down a bit now."

"Huh." Berry waited for Derpy to steady herself before stepping away. "Y'sure you weren't pent up in general in addition to all'a this?" She gestured at the tub, unperturbed.

Derpy huffed, partly still panting for air, partly exasperated. "You've got to be a robot."

Berry responded with a non-committal "Mhm," as she inspected splatters of milk around the room. "If you really wanna be bigger you'll have to do that, I dunno, in the garden or something. Ought to plant some high hedges for that case."

"That was the greatest orgasm of my life, Berry!" Although to be fair, if her breasts and her potential output did get bigger, a session like this could be a nightmare to clean up. Repeating it outside where a passing pegasus might see what she was capable off did sound nice, though.

"And I'm very happy for you," Berry agreed mildly. "I had fun, too." She rubbed her chin, switching topics suddenly. "I think we ought to buy some weights. A bench, too," she stated eventually.

Derpy wasn't sure what to do with that. "Uh ... why?"

"Because I'm gonna show you how to work out proper," Berry claimed more decisively. "Wouldn't wanna wake up one day and have your tits feel like a burden, yeah?"

That didn't seem possible. Still, she hoped to grow the sort of rack that needed to be seen to be believed and it would be terrible to lock it away because moving was too strenuous. However, right at this moment she had very little use for that train of thought.

"Okay." Derpy shook her head. "Okay. Berry Punch."

"Yeah?"

"I would really enjoy if you grabbed my tits and treated them rough. Doesn't have to be tonight." She held up a hand to signal that she wasn't done. "That's just, uh, animal pleasure. It'd be worthless without, uhm ... without uh, us having a mutual thing. Please tell me if you think I could pleasure you." She was tempted to add 'you bloody robot', but stopped herself. "If you don't think you'd enjoy that, I'd still really appreciate it if you could just try treating them gently while we cuddle. I'd find that very soothing."

Berry grinned widely. "Could I get that on some nice card stock with calligraphy? You'd have my RSVP post-haste."

Derpy just gave her a stern look.

“Alright, alright.” The earth pony pinched the bridge of her muzzle. “I guess we’ll talk about our relationship now that it turns out your jugs are fun for both of us. You clean up your mess, I’ll prep some drinks and get my notes.”

“Your notes,” Derpy echoed, dubiously.

“Look, my therapist has way better words for this stuff so I sometimes take some notes while we talk.” Berry turned and walked out without additional explanation.

-

Once Derpy had finished cleaning up after herself and putting on some fresh panties, she found Berry already in the kitchen, wearing a clean shirt. The bigger mare was seated at the table, a small notebook in front of her. Two small glasses filled with white sat on the table. Sloppy, homemade white russians, if Derpy judged her friend correctly. She usually did.

Berry grinned at her and picked up a glass. “A toast to the last milk we’ll ever buy, yeah?”

Derpy took a seat, grabbed the other glass and gave it a hard stare for several seconds. “Alright, doesn’t feel wrong.” She held out the glass so they could clink them together.

“What, drinking alcohol, or foreign milk?” Berry didn’t smirk or grin or otherwise indicate that this was anything but an entirely legitimate question.

“Both, I guess.” Drinking alcohol while nursing was divisive, but having realized just how much milk she had on tab, Derpy was inclined to think that occasionally sharing a cocktail with her friend would be meaningless. Given the inexplicable, probably magical nature of her lactation, it was probably legitimate for Berry to wonder if Derpy would have a problem with herself or others drinking regular cow’s milk.

That would have been rather concerning, considering Derpy was also fairly sure she hadn’t been quite so preoccupied with her own tits previously either. Certainly her new gifts came with new sexual fantasies and arousing ideas, but not with obsessions that would compromise her ability to be a mother to two small fillies. Derpy resolved herself to grow only gradually over the coming years.

“Right. Down to brass tacks.” Berry sipped her drink, watching Derpy with alertness. “Why the sudden interest? We gotta be deliberate about this.”

Derpy fidgeted. “I already love you. I can’t see myself trusting anyone else as much as I do you. You’re big, strong and reliable, makes me feel protected, and less shaky when the kids are being stressful.”

“That’s flattering, and I care a lot for you as well.” Berry said with no particular emotion in evidence. “But you’ve said as much before, so my question stands.”

“These are meant to be shared,” Derpy cupped one of her breasts. “I’ve been getting horny a lot lately, but it’s more important to me to share them with you in a way you’re comfortable with.” She bit her lip. "Sorry about your hand, earlier."

Berry snorted. “Don’t get me wrong, I’m down for it. I just don’t know that it’ll add another level of depth to our relationship for me, and I worry that’d make it worse for you. At the same time, you shouldn’t worry that I’m just doing it to do you a favor. I’m willing to see what happens. I’ve never slept with a pony I actually cared about.” She emptied her glass. “Unless you end up being really bad at pleasuring another mare, of course.”

“A few years out of practice at worst,” Derpy stated confidently, giving Berry a mock glare. “Considering your lack of reaction so far, shouldn’t I be more worried that sleeping with you'll be about as sexy as stacking lawn chairs?”

"We both know I got the easy job." Berry scoffed. "Here, watch me." She pointedly started staring at Derpy's rack. After a moment, she started worrying at her bottom lip with her teeth.

Derpy squinted in vague confusion. "Are ... are you trying to look like looking at my boobs gets your worked up?" She'd never noticed the earth pony give an attractive individual of any tribe or gender a second look. And even though she wasn't sure what her friend was going for, it seemed as though her gaze brushed across Derpy's skin like feathers.

Berry shrugged but didn't look away. "A'ight. Can't all be winners." The mare opened her eyes wider, then slowly allowed her mouth to drop open until she was regarding Derpy with an almost comical expression of dumbstruck awe, something one might find on a farm-pony seeing Canterlot castle or catching a glimpse of the Princess for the first time.

Ponies should be in awe.

Her nipples grew achingly stiff as Derpy squirmed in her seat. She wanted to be bothered by how easy it was to get her horny again, but the emotion just wouldn't come. The attention felt too good. Too right.

"Heh. Y'know while you cleaned up, I tried to have a bit of a think on how to escalate your fantasies," Berry smiled with obvious mirth. "S'not even necessary. Small town like this, you wouldn't need to be much bigger to get looks like that regularly."

Derpy’s breasts tingled and grew warm. She thrust out her chest to make them seem even more prominent. “I want strangers to stop and stare,” she gasped out, flushed with arousal. “I want everyone to be in awe as I get bigger … but not you. Not the girls. You’re family. My boobs should be normal to you.”

Berry nodded at that. "Still ... bunch of folks passing you in the street? They might be impressed, but they'll only know the half of it, hm?"

Show them all.

Even an entirely imaginary audience ignorant of Derpy's newfound abilities got her breasts fired up. She whimpered as they grew taut. Normally they retained an attractive, seemingly natural shape, although with astoundingly little sag considering their recent growth and Derpy's habit of foregoing bras. Now they were rounding out under internal pressure until they looked fake as they sat high and proud on her chest, aching for release. "Don't wanna make a mess."

Even the throbbing ache of feeling overstuffed with milk made her happy. It seemed like a brilliant idea to try and go through a day feeling like that, every stray look making her hornier and hornier until she simply erupted in front of a surprised audience. Perhaps afterwards she'd simply go about her business with milk continuing to soak through her top.

"So what, when you get randy, you need to get rid of some arbitrary quantity to appease your tits, is that it?” Berry sounded amused, but the questions did seem sensible.

“I love that phrasing,” Derpy sighed in contentment. “Never happened when I was feeding our daughters ... but I bet letting go now would be incredible." Small drops of milk beaded on her nipples, escaping her control. She'd never previously had to struggle to hold in her milk. Derpy still felt entirely convinced that her glands were perpetually productive, and earlier she had clearly spilled more milk than her boobs could realistically hold, so feeling so desperate for release now didn't really fit the facts unless it was just another way for her amazing tits to provide pleasure.

“I don’t really get that. You got infinite milk, yeah?”

“App -hff- apparently!” She found herself loving that word. Infinite. Oceans were vast beyond most ponies' ability to conceive of, but they were ... finite. Even measurable, with the proper tools and calculations.

"And I didn't even touch you." Berry grinned smugly.

Derpy wanted to be annoyed that her partner had gotten her all hot and pent up just to prove a point, but for some reason, she loved this as well. Her trust in Berry was absolute, so it was easy to enjoy the power the other mare had over her just by sparking mental images. "You have the best ideas," she eventually commented, voice thick with her lust.

Berry emptied her drink, then slid the glass across the table towards Derpy. "Let's have a refill, yeah?"

She eyed the glass skeptically. Her nipples felt like she'd just splash milk across the table if she touched them now. On the other hand, she couldn't think of an additional reason to refuse. Feeding Berry her milk, more than she'd tried earlier, would complete the set, as it were. She'd have provided for her whole family.

Derpy finished her own drink before standing up shakily, expecting at any moment to go over the edge of climax and lose her footing.

She wasn't confident in her ability to just fill one glass without her other breast also letting down. Inexperience hampered her aim, but she was genuinely surprised by how cooperate her breasts were being. Even in their engorged state, handling them gently remained soothing. "Celestia, this is weird."

"Hm?" Berry tilted her head slightly, waiting for Derpy to elaborate.

"I'm really, really horny right now, and I got more pleasure out of my tits today than I ever got from ... any part of me. But prepping a drink for you feels ... uh ... wholesome. I'm not getting off on this." Derpy hummed in contentment.

"So they'll get you off practically at will for all the effort it takes, but once you're actually feeding someone they're all business?"

"I'm sure if you found this erotic at all they'd accommodate us both," Derpy guessed as she stopped her let-down with an effort of will. "I'm glad there's still a line between pleasuring myself and actually providing for ponies."

Berry snorted. "Yeah, like that was ever in doubt. Discovering you got magic tits was never gonna make you less ... you."

"I never had fantasies about ... bothering people with my boobs before." Even as Derpy said it, she couldn't help feeling some resentment about having to put on a shirt when going outside. She slid Berry's glass back to her.

"Yeah, okay, but I don't care about the rubes here, I think it'd be funny to mess with them." Berry rolled her eyes. "Besides, this is the heartland of Equestria. The only ponies who gotta worry about going hungry are kids getting sent to bed without dinner." She scowled momentarily. "No one's gonna think of your jugs as a food source, because that's totally unnecessary. So they might as well be fun for you."

Derpy frowned. That truth was unaccountably difficult to hear, but she couldn't really deny it. At the same time, it made her more eager to grow larger, milkier, until her awesome tits were burned into everypony's memory. It was fine for her neighbors to view her abundance as some kind of nuisance as long as they knew about it at all. "Could you stop calling our neighbors that? I wouldn't want the kids to pick up on in. They're gonna be a lot worse at playing nice in public than you are once they talk."

Without responding, Berry picked up her glass and drained it slowly. The sight made Derpy happy, and she felt a big smile forming on her face. Simultaneously, the pressure in her breasts, which hadn't much diminished from filling up two small glasses of milk, began to recede, her arousal cooling slightly. She felt considerable satisfaction, undiminished by the knowledge that Berry didn't really need her milk, either. The acknowledgement seemed to be enough, her best friend would never fear hunger again while Derpy was around.

"That's fair," Berry conceded eventually. "See? You're still worrying about the girls, first. I want the kids to grow up safer and happier than I did. Raising them is gonna stay job number one, yeah?"

“Of course,” Derpy agreed, happy to have Berry to keep a level head. “I’ll pace myself. Keep them as a hobby. I want to have huge tits, but I want to be someone who does right by her family.” It was for the best, really. If she didn't have responsibilities she'd probably spend all day playing with herself, considering how easy it seemed to get herself horny now.

She picked up her own glass for a taste. As she'd expected, it was just milk, recognizable despite the difference to cow's milk. Drinking from herself didn't do much for her, although she looked forward to being just the right size to suck on her own tits, since that would be a great party trick while she was small enough to pull it off. After all, impressing other people with her breasts did seem very appealing. She probably wasn't far off from it.

"Didn't expect anything else from you," Berry shrugged. "So, you simmering down there?"

"Sort of?" Low-key pleasure still sweltered within her, ready and waiting to spike again. Like a soda bottle which had been vigorously shaken, the mess wouldn't appear until the lid came off. But there was no urgency to it, and her rack had returned to feeling reassuringly, rather than desperately, full. Derpy thought she might be able to ride it out without getting herself off again.

"Great," Berry sounded all business, putting a pen to the pages of her notebook. "I'd like a workout room in the basement, since we can just lock the door and keep the kids from going down there. Together with that I think we could use a large shower room or something with good drainage. I'm tentatively open to see how much fun we can have without worrying about more clean-up than hosing everything down."

"Berry ..." She wasn't going to cool off with talk like that. Derpy took another drink, hand slightly trembling, while the other went to massage her breast practically of its own volition.

"Our savings still look good," the earth pony continued. "However, we're gonna need a better saving plan than just not buying milk anymore." Berry clicked her tongue. "I feel like we ought to budget for removing all the carpets, put in tile and, ideally, drains in every room. That'd seriously cost us, though. We can use rugs to soften the floors up, but I'd prefer any unexpected explosions to be as easy to clean as possible."

Derpy's gentle massage turned into roughly groping herself. No sudden spray of milk in evidence – perhaps having 'fed' Berry really had appeased her eager glands for a while. She was looking forward to experimentation to figure it out. Right now, the pleasure of her own touch was electrifying. There was no sugarcoating it. Despite the future costs, the world having to be adjusted around her tits, her milk and her future growth was insanely hot to contemplate.

"Feels so incredible," she managed to say through the fog of sheer delight in her head. "I wouldn't know ... how, how to make you feel anything like it," Derpy eventually admitted.

Berry evidently struggled not to laugh. "This is too easy."

Derpy panted. Release felt so close, so tempting. She reduced the workout she was giving her rack, only brushing her fingers gently over their skin. It took the edge off, and she sighed happily, wondering if that was to be her new normal. She held up a hand to prevent further comments and closed her eyes.

Despite every sensation sending sparks of pleasure through her body, her mind seemed relatively clear. Sure, maybe her brain was a tiny raft on an ocean of lust, but until the next wave dragged it under, she could think mostly straight. She successfully ran down a mental list of chores which needed doing the rest of the week. Although she intermittently found herself wishing to feel her friend's strong hands on her body again, the brief distraction hadn't introduced errors as far as she could tell.

"I could live like this," she decided, giddy with elation. "Berry. Just imagine ... I'll be walking around like ... like eight tenths of the way to a brain-melting orgasm, enjoying how awesome my boobs feel, but only you know how easy it'd be to wander up and whisper something in my ear that'll set it off."

While Berry did smile fondly at her, Derpy was thrown off by her response. "Why me?"

"I want you to have fun with these!" She lifted up her breasts slightly. "You're important to me ..." Derpy trailed off. Her rack was attractive, but its size merely uncommon big for a mare of her tribe and build. She didn't resent that, but she could still dream. She wondered how enormous her tits would have to be so Berry could sit on them with her legs over Derpy's shoulders while she got eaten out. How heavy would they have to be to bear the other mare's weight without shifting apart and having her slip down into Derpy's cleavage?

She took a few more seconds to dismiss the image and take slow breaths. That sort of thing was a goal for years in the future, when the kids were near-grown and would mostly need her for emotional support.

At Berry's raised eyebrow and gesture towards her mouth, Derpy wiped off a bit of drool.

"Don't worry about me too much. All the equipment works as expected," Berry shrugged. "Did you just convince yourself you can go out in public with your nips ready to poke out eyes and you spacing out and drooling every so often? I expect the ru- these rural types to be thick as hell but they're not that stupid."

Derpy found herself grinning lewdly. "I'm trying to be embarrassed, but I can't." Frankly, she wanted to shout from the rooftops that she could cum harder and better than ever before, that her boobs produced only the finest bespoke climaxes specifically for her, but that was both unacceptable and perhaps pointless. She wasn't sure another mare would even understand that Derpy's claims were possible. "I've got to practice staying functional." She lowered her head to indicate her chest. "Because I hope these'll get even more intense."

Berry's long-suffering sigh was disarmed by her smile. Still, she turned more serious. "I'm willing to play along, but let's postpone the actual, y'know, sex for a bit. Would like to bounce some of this off the doc."

Slightly disappointing, but sensible. It wasn't as though Derpy needed help to have fun, and Berry tended to be sufficiently awkward with real emotions that it was probably a decent idea for the mare to talk to her long-time therapist.

They were both distracted by noises. Probably one of the kids had woken up, and might wake the other.

Berry got up. "I'll check. Why don't you get ready for bed? I'd join you, if you want."

"Sounds great!" Derpy found her friend very comfortable, although usually their daughters served as the excuse for family snuggling time.

Later, in the darkness of her room, Derpy sighed happily, enjoying her friend's close proximity. Berry had even been willing to touch one of her boobs again, absentmindedly rubbing at it in a way Derpy found soothing.

"Not worried about your, uh, your libido, Derps?" The sleepy mumble was endearing, as was the concern for her.

"I can handle it," she stated confidently. "Besides, it's probably necessary."

"Huh." Berry shifted slightly. "Run that by me?"

Derpy curled herself closer into Berry's side. "I'm confident, weirdly confident, that I can grow more." And she was really looking forward to it. "If that's true and I haven't just gone mad, then one day, years from now, my, my options for entertainment are gonna be limited by my size."

Berry's answer took long enough Derpy had started to suspect she'd just fallen asleep. "Tha's stupid," she earth pony muttered. "If you were stuck to your tits I'd bring ... books. Games. Newspapers. 'Sides. You take it that far, I expect ya to be busy running at least one dairy company. Milk, yoghurt, cheese, icecream, the works. At least one weather factory to spread the love."

Derpy shivered. "Mhm." She'd certainly be pulling up those mental images again going forward. The anticipated crashing surge of arousal arrived as more of a languid wave, like melted chocolate, spreading warmly from her tingling breasts through her body towards her nethers. It'd be a trivial effort to make herself cum, but there was no urgency. Her desire didn't diminish the satisfaction of the current situation, cuddled up with her best friend in the world, feeling supported and protected.

As she drifted off to sleep, mind fuzzy with both sleep and lust, she found herself dimly appreciating that her boobs had their priorities straight.