“Oh, Nikki,” she said, embracing her sister in a tight hug. “I’m so glad you could make it.”

"Yeah, of course, Darcy. What did you want to talk about?” The sisters stepped into Darcy’s apartment and sat at an ancient looking wooden table decorated with runes and other symbols. She really tries for that witch aesthetic, Nikki thought.

“Okay, well, I want to start working on a potion, but there’s a little obstacle in the way, and I was hoping you could help me with it.” Nikki looked at her inquisitively. Darcy continued. “Most potions use water as their base, which is easy, just go fill up the cauldron from the tap, you know? But this one is different. The base I need… is breast milk.”

"How would I help with that? I’m not lactating. Mom gave me the same tiny boobs you got, anyway, so it would take a while to fill an entire cauldron.”

"You’re not lactating now. With one quick little spell I could change that and give you the huge boobs you always wanted.”

Nikki looked down at her chest, trying to imagine herself with bigger breasts. The lactating part worried her, though. “I wouldn’t… always be making milk, would I? Like it’ll stop after you get what you need?”

Darcy smiled comfortingly. “I can reverse the lactation, yeah. But I won’t be able to make your boobs smaller. Which is why I don’t want to do it myself.”

Nikki looked thoughtful for a second, mulling over the decision. “Sure. I trust you not to make me explode or anything, sis.”

Darcy bounced in her seat excitedly. "Yay, thank you Nikki, you’re great! There’s just a little bit of prep we need to do.”

Later that morning, Nikki and Darcy had everything ready for the spell. Nikki was topless and standing over a stereotypical witch’s cauldron. Darcy had drawn circles of runes around her breasts and nipples. “So you’re going to start chanting the incantation or whatever, and I have too drink all of this?” Nikki held up a half gallon jug of milk.

Darcy was flipping through pages of an old leather bound book, double checking her work. She looked up for a second at her sister. “Yup. Without that you’ll just grow huge boobs, but I need your milk too, so drink up when I start. Ready?”

Nikki turned to face the cauldron and took the cap off the milk jug. “Ready,” she confirmed.

When Darcy started her incantation, Nikki lifted the jug to her lips and started to drink. The runes on her chest started to glow dimly and she felt a heat develop in her breasts. As best she could, Nikki tried to look down at her chest. She couldn’t see much of it, but she thought she felt the weight pulling on her increasing. Nikki’s breasts had started to grow. Yeeesss, she thought, time to get huge tits! Just gotta get this lactation thing out of the way…

Nikki’s boobs grew and grew, gently gaining circumference while Nikki chugged down the milk. By the time she had drank half the jug, her boobs had slowly grown to rival grapefruit. The spell caused them to grow smoothly, steadily increasing in size and weight. Nikki moaned quietly as the heat in her chest turned to a soft pleasurable quality. She slowly noticed the sensation of fullness in her breasts. My milk must be coming in, she thought.

As they grew and filled with milk, Nikki’s boobs started to firm up; appearing very perky despite their weight and the added weight of the milk inside them. As the jug lightened, Nikki moved one hand down to a breast to gauge her size. She was pleased to find they were more than a handful now, probably E cups, and still growing. Her hand explored a large, firm, growing breast, and felt a nipple. She was temporarily surprised to find it had grown as well, but it mma sense to her that they stay proportionate to her swelling boobs.

Nikki finished the milk and dropped the jug haphazardly, letting it fall to the floor. The pressure behind her nipples was getting intense, almost uncomfortable. She hoped she wouldn’t produce more milk than her tits had space for. By now, her burgeoning boobs resembled melons, rivaling cantaloupes for size. Nikki’s plumping nipples were like dimes. She gasped as the pleasure of her boobs growing and the discomfort of the milk pressure competed with each other.

"How… how big am I going to get, sis?"

Darcy had finished her incantation when Nikki had finished the milk. She walked over to her transforming sister to observe her progress. Darcy shrugged. “It depends. Apparently the spell affects everyone differently. Damn, you’re getting huge,” she said as Nikki’s breasts swelled larger than her head. Darcy reached forward and quickly pinched one of Nikki’s nipples. Nikki cried out and fell to her knees from the burst of pleasure she felt from it. “Everything is going properly as far as I can tell. The spell is supposed to make your nipples really sensitive to make the lactation enjoyable.”

The pressure inside her tits kept mounting, and it was clear Nikki was producing milk more quickly than she was growing new space to contain it. She desperately tried to get her breasts to express her milk as they kept growing, the bottom of her boobs rapidly approaching her belly button. The pleasure from tugging on and playing with her nipples was intense, but she couldn’t get the milk to flow despite the enormous pressure in her breasts.

As she watched her breasts continue to grow, Nikki wondered how all her life choices had lead up to her current situation. She knelt in front of the cauldron, her nearly painfully full boobs sitting in her hands. Her volleyball sized breasts made her hands look so small, she thought. The pressure grew faster than before, and Nikki figured her tits had stopped growing. Without the pleasure from the growth, her boobs began to feel painfully overfilled.

Just when she thought she couldn’t handle the pressure anymore, her breasts finally- finally- released. Thin white streams began to leak from her sizeable nipples. Nikki sighed with relief as the pressure began to slowly decrease. She began to pull on her nipples, trying to get her milk to flow faster. Nikki was struck with intense pleasure again as she manipulated her nipples. The feelings made her world shrink to the two points of space that were her nipples- nothing else mattered at this point. Suddenly, her milk started to gush from her nipples, and she could barely focus enough to keep milking herself. The pleasure mounted quickly as her milk flowed into the cauldron, nearly filling it to the brim already. A damp spot formed on her jeans as her tits kept pushing her milk out.

She came suddenly, her hands falling from her nipples. Unable to control her muscles through her orgasm, Nikki fell onto her back as her breasts continued to pump milk through her super sensitive nipples. Her milk continued to spurt out of her tits, covering Nikki’s body and the floor, pooling around her. In the back of her mind, Nikki wanted to reach a hand down to get damp crotch, but as she rode one orgasm to the next, seamlessly, she had lost control of her body. All she could do was lay on the floor and lactate. The floor around her was quickly covered in milk, and it soaked into her jeans and her hair. As her legs shook with her continuous orgasms, the sensations overwhelmed her brain, and Nikki fell unconscious.

Nikki woke up on a couch with a blanket over her. The first thing she noticed was that she was dry. Before she moved, she wondered if it had all been a dream. She tried to sit up, however, and discovered everything had really happened. Nikki felt her huge boobs move as she tried to get up, the bottom of her tits touching her thighs. Bracing herself, Nikki flung the blanket off herself. She gasped sharply when she saw her huge boobs. They covered her torso, huge and warm. She estimated her nipples were at least eight inches above her torso. And her nipples were gigantic in comparison to how they had been before this morning. The pink nubs were a half inch thick, at least, and the diameter of quarters. Slowly, Nikki turned to get up from the couch. She leaned forward as much as she could, squeezing her huge boobs between her torso and her thighs, and pulled herself upright. Standing, she could really see just how big her tits were now. She walked towards the kitchen and felt her boobs wobble with each step. They covered her torso down almost to her hips and obscured most of her arms- her breasts were now the widest part of her.

In the kitchen, she found Darcy working on her potion. Her sister’s eyes lit up when she saw Nikki.

“Oh, you’re awake, finally! That’s great. You came so much you knocked yourself out for a couple hours, so I dried you off and floated you over to the couch.”

Nikki could feel some subtle pressure in her breasts. “You didn’t stop my lactation though?”

"I wanted to wait until I could ask you if you wanted me to, sis. It seemed like you enjoyed it, but I can dry you up either way.”

Nikki thought for a second. It did feel amazing when the milk flowed through her nipples… and who knew what kind of properties her magically developed milk might have? She smiled.

“No, Darcy, that’s alright. I’ll keep the milk. Could you conjure me up a bra and a shirt though?”