Foalsitting Aftermilk... math.

Rainbow Dash landed outside the cottage near the edge of a forest. Looking around she saw all of the animals the Fluttershy took care of. It was early afternoon and there were plenty animals laying about in the sun.

Rainbow knocked on the door before letting herself in.

"Hey Fluttershy! You in here?" She said loud enough to be heard in any part of the house.

Fluttershy jumped at her friends entrance, especially since she wasn't very far from the door herself.

"Oh, her Rainbow. How are you this afternoon?" She said timidly.

"I'm okay, though I ran out of milk this morning and was wondering if you had any to spare?" Rainbow stated holding up an empty milk jug.

"There's some in the fridge." Stated the meek mare.

Rainbow walked over to the mentioned appliance and opened the door. Looking in the fridge she noticed a full jug of milk and a bucket with maybe another quart in it. Swapping her empty jug with the full one she closed the door.

"Thanks for this Fluttershy. I would've just used my own milk, but I sorta use it as an energy drink. Figured you'd have a bit and that I could save some bits." The rainbow maned mare said, her eyes on her friends prodigious chest.

"Anytime Rainbow. I add some to the animals food and use some for myself, but I've been making so much I just don't know what to do with all of it." Fluttershy said.

Rainbow gave her friend a hug, noticing something when she pulled back.

"Fluttershy, don't you think you should wear something other than your sweater? It's so hot you've sweated through it." Rainbow remarked, patting her own shirt to see if it had gotten damp.

"Oh, well um... I'm okay with wearing it, it's not that bad." stumbled the shy mare.

Rainbow lifted the bottom of the sweater up enough to see that Fluttershy had a shirt underneath. When she did so a hand towel feel from underneath it and landed wetly on the floor.

Sighing she said "You can't just stuff a wet rag in your shirt to keep you cool. It does help a bit, but there are other issues."

Rainbow then lifted the sweater off her friend entirely while she stood there timidly. Another towel joined the floor and Rainbow got a good look at what Fluttershy was wearing. Her nipples were clearly visible through the shirt from being wet from milk. Picking up one of the towels told Rainbow that they had gotten soaked with milk as well.

Looking at her braless friend she raised a questionable eyebrow.

"My bras had gotten so stretched out over that last couple months I can't wear them anymore. I was on my way to see Rarity to get some new ones." Fluttershy explained.

"If you've grown that much over just a couple months there might be something else. I'll go get Twilight and meet you at Rarity's okay." Rainbow said before taking off, milk jug in hand.

Fluttershy grabbed a couple new hand towels and placed them over her chest before putting her sweater back on.

Fluttershy entered the Carousel Boutique and walked over to her friend who was sitting at a table working on a project. There were a couple others in the store looking over some of the clothing.

"Hey Rarity." She greeted.

"Oh Fluttershy darling, how are you today?" Rarity asked.

"I'm good, but I need a couple new clothes." Fluttershy said weakly.

"What kind of clothes are you looking for?"

Fluttershy leaned in close and said almost to quietly "Bras."

Rarity smiled at her timid friend. "Why don't you head back into my kitchen. I have some tea set up back there so help yourself. Shouldn't be too long before I can help you."

Fluttershy nodded and headed back. She made herself some tea and enjoyed some of the finger food that was laid out.

After some time Rarity came back and joined her. They had a cup of tea and chatted for a few minutes before moving up to Rarity's personal workroom.

Rarity watch as Fluttershy took off her sweater revealing the hand towels and soaked through shirt. Once Fluttershy was standing before her topless she pulled out a measuring tape.

While taking the needed measurements for making her friend a new bra a knocking was heard.

"One moment darling, I'll go see who that is and deal with them." Rarity said before leaving the room.

A couple minutes later she returned with two of their other friends in tow. Rainbow entered the room first, shortly followed by Twilight. Fluttershy gave them a little wave while her other hand covered her breasts.

Rarity nudged her hand away and returned to taking measurements.

"Fluttershy, Rainbow said you were having some sort of issue from the lactation spell." Twilight said, looking at her friend.

"I wouldn't say an issue, but they've grown so much over that last few months, and I produce more milk than I know what to do with." Fluttershy replied.

Twilight hmmed. "Is it okay if I check a few things out on you?" She asked.

Her friend nodded and Twilight began working some spells. Her magic enveloped Fluttershy's tits and told her some of what she needed to know.

"Fluttershy, when did your breasts stop growing previously?" Twilight inquired.

"Well, I've only been getting about a half cup each year." Fluttershy answered timidly.

Twilight raised an eyebrow before asking, "Wait. They didn't stop growing once you got past your teens?"

"Should they have?" Questioned the shy mare.

"Yes. I think I know what happened. You have Gigantomastia." Twilight stated.

"Giguto Masteven?" Rainbow asked as she ate the snacks Rarity had set up.

"Gigantomastia. It means large breasts -" Twilight started.

"I could've told you Fluttershy had big tits." Rainbow interrupted.

"It means large breasts that don't stop growing. Your body never got the signal telling it to stop the growth. You said it slowed down, so my lactation induction spell must've restarted it." Twilight explained, a little annoyed at Rainbow Dash.

"Oh, is there anything you can do." Fluttershy asked worriedly.

"I'll have to check. The spell's effect ended with you already so that's not an issue. There's nothing to worry about Fluttershy. Gigantomastia isn't a serious problem." Twilight said before heading back to her castle to study.

Rainbow left after finishing up eating all the finger food leaving just Rarity and Fluttershy.

"You know darling. A corset would be far more suitable for you. It won't get stretched out like a bra, and they were originally designed to give support to mare's with sizeable endowments." Rarity said, laying out some fabric to make some nursing bras.

"We'll need to schedule a day for me to come over. I want to get some more accurate measurements of your bustline when you are filled and empty of milk." Rarity continued.

"Sure no problem." Fluttershy agreed.

They chatted about some of the gossip going around town before setting up a date for Rarity to visit Fluttershy. Rarity also washed the shirt and sweater her friend had worn over before giving them back dry and with a couple new bras for her.