The doorway opened with a quick swish, clearing the way into the laboratory that Mei Hatsume called home. She had been busy working on inventions for the students of 1-A, eager to supplement their activities in exchange for a little bit of promotion. Today, she was going to meet one of the students who had most interested her when the Support Class was putting together costumes.
"So, Mei, what are we going to do tonight?" asked Mina.
"The same thing I've done every night, Pinky. Learning all about 1-A's Quirks! My babies are as much fashion as they are science. I need to know every contour of your form if I ever need to upgrade your costume. You haven't put on any weight since you started hero training, have you?" asked Mei.
"Might've put on a few kilos from all of Satou's sweets," said Mina, playfully slapping her stomach. "Look at how it jiggles."
"I can hear it bubbling," said Mina. "How does your body work anyway?"
"The more acid there is in food, the more of it I store in my body for later. And the rest turns into energy and..." Mina said.
"You can stop there, I get the idea," said Mei. "I was amazed that you got as far as you did in the sports festival. It makes sense you'd want to use your limbs first, but can that acid come out from anywhere on your body?"
"I can't direct it as well, but yeah," said Mina. "I see where you're going with this."
Of all the costumes in Class 1-A, Mina's was one of the flashiest. The pink and green bodysuit, short vest with fur collar, and white domino mask had been decided by what Mina thought was fashionable. The fabric was designed to be resistant to her own acid, though if Mina concentrated enough, she could coat the outer layer of her outfit in a slime that created an impromptu shield.
She wasn't going to be wearing that today. Mina stripped down out of her school uniform, leaving her in only a deep violet pair of underwear. Wild, frizzy pink pubes, of the same thickness and curliness of her hair, poked through the edges of her panties. Mei's body warmed up, her heart throbbed with excitement. It was the same feeling she felt when working on her inventions. It was more erotic than sexual, an overwhelming desire of the knowledge to know, in all senses.
Mei stripped down herself, removing even her panties. The only thing was wearing was her goggles. For Mei, this was the purest form of nudity. She didn't care that her nipples were stiffening before Mina's eyes. Her thirst for knowledge exceeded all else. Here, the cold breeze blowing through her lab felt as refreshing as a summer day. Mei strapped on a pair of gloves, and set about getting to know Mina's body. Her touch did not have the clinical sterility of a doctor. There was passion and lust in her fingers. The kind of touch that Mina was receptive to.
The acid that had affected the pigmentation of Mina's skin affected her all over. Compared to Mei's pale pink nipples, Mina's were a dark, almost purple shade of pink. They boldly stood out against her skin, glimmering with a faint sheen from the layers of sweat and acid that had built up over Mina's body.
"Stare all you want. I've shown 'em off before," said Mina.
"They're beautiful," said Mei. "They're nearly the same shade of purple as Midoriya's glans!"
"What have you been looking at his peen for?" asked Mina.
"Gear fitting, reproductive potential, masturbation material," said Mei. "I'll bet Kirishima can get super hard. He is your boyfriend, I'm guessing?"
"I mean, I've given him a handy, but he can't keep it up for that long," said Mina, smirking about the experience. Mina pushed up her breasts with her hands, letting them flop about. They weren't the biggest ones in class, Yaoyorozu outranked everyone, but they were at least a cup size bigger than Uraraka's.
Mei took a sniff of the air in the lab. It smelled like sweat, but several times more potent. She asked Mina to raise her arms. Mina had a light bit of armpit hair. She had never shaved it because it helped trap in acid, which could be useful as a last-ditch strategy. The hair had the same color and sharpness of her pubes, with a smell that stung the inside of Mei's nose.
"Did you work out before coming here?" asked Mei.
"Basic training, yeah," said Mina. "I wanted to shower, but you told me not to."
"That sweaty smell is incomprehensibly good," Mei said. "Hopefully it doesn't interfere with my babies, but I want to see all the kinds of acid you can produce. Sweaty acid, milky acid, lubricating acid..."
Mina laughed. "The girls can always tell when I use the toilet. Almost melted the seat off when I pissed in the middle of the night. Anyway, that's where the school budget went last quarter."
"Simply fascinating," said Mei. "The reason why I called you here is this."
Mei presented a pair of breast milk pumps, shining with the gleam of reinforced materials. They could contain Mina's acid without neutralizing it, allowing for an easy and sensual method of collection.
"I could just shoot it from my hands," Mina said.
"You don't understand, Ashido," said Mei, squeezing down on the pumps. "This way is so much more erotic. The intersection of Quirks and technology that gets me off in ways ordinary masturbation can't! Now, let us draw forth from your bosom!"
"Is this for one of your tools?" asked Mina.
"Yes. I want to help you make some gear that will be useful in future heroics," said Mei. "This is all for the sake of research!"
The suction cups wrapped around Mina's nipples, pulling them towards Mei's gaze. While Mina played with her nipples nearly every day while masturbating, this sensation was far more intense than she was expecting. A small spurt of acid shot from her nipples, flowing into the cup. A faint hissing noise echoed from within the cup as the acid settled on the bottom.
"It's watery," said Mei.
"To get the real gooey stuff, you have to work it for a little bit," said Mina. "My nipples are feeling sore already."
"How so?" asked Mina, taking notes.
"The acid in my areolae, maybe," said Mina. "You roped me into this. Squeeze my tits, Hatsume!"
The sweat building up on Mina's breasts was slightly acidic, and dangerous to touch while her emotions were running high. Mei grabbed ahold of Mina's ample bosom, massaging her pink skin and watching the acid come out in fits and spurts, being drawn into the tubes of the machine.
Mei had first become interested in Mina when she heard a rumor about a free study period. Midnight left the students alone, telling them to play around with their Quirks in a safe environment. This had come moments after a sex ed class, so the students were told to think about how their Quirks might affect their sexual growth.
Tension in the room was awkward, until Mina stepped up to the front of the classroom and broke the ice. She unbuttoned her uniform shirt and pulled down her bra, exposing her breasts to the class. No boys were in the classroom at the moment, so she had no embarrassment about doing so. The girls had already seen each other in the locker room several times, where it was treated as a routine thing.
"Mina's party trick - 'breast milk'!" Mina said happily.
She squeezed down on her breasts, sending a small squirt of what looked like milk across her uniform and onto the desk. It was neutral, being as safe as tap water. It dripped off the desk, falling onto the floor. Momo was shocked, wondering how they could get the classroom clean before Midnight got back.
"The acid that comes from my chest isn't harmful, so drink up!" said Mina.
"Looks delicious to drink," said Tsuyu in the corner.
The reason was just as Mei had speculated. Mina's primary acid was a congealed, directable form of her sweat, thus why it formed on her skin. She could get similar effects and varying kinds of acid by passing it through other pores on her body. It may have been an acid she could freely control, but it had come from her mammary glands. In a way, it was a diluted form of her breast milk. She'd never had a boyfriend and never had sex beyond rather frequent masturbation. Quirks were an amazing thing indeed.
Mei continued to massage Mina's breasts, starting from the back and moving her way upward. Her touch was gentle, almost clinical, and the latex made Mina feel naughtier than it otherwise would have been.
"You can be a little rougher," said Mina. "I do worse than this when I masturbate."
"Impressive, you use your hands," said Mei. "I've always preferred toys."
"Awesome," said Mina. "Lend me one of yours sometime."
"Oh, I will," said Mei, with a coy grin.
Mina's areolae were producing acid milk at a rapid rate, filling the cups much quicker than Mei had expected. Mina moaned and let out cute grunts as her breasts were emptied into the cups. She knew that her body produced acid like it made saliva. It would be very difficult for her to run out. She could stop this any time she wanted, but taking the afternoon off and getting sexually pleasured by Mei was more enjoyable than she could have anticipated.
"This isn't going to work," said Mei. "We're not using gravity well enough."
"Hey!" Mina said, pushing up her breasts with her hands. "My boobs aren't droopy. They're still young and perky!"
"I meant your position," said Mei. "It'd flow much faster if you were on all fours."
"I'm not some sort of cow," said Mina. "It looks like we filled the first two cups already."
Mei reached into the cabinet in her lab and produced four more cups. She untwisted the first bottle from Mina's breast pump, and sealed her acid milk with a satisfying pop noise. A few drops of milk fell into the third and fourth cups as Mei secured them to the end of the pumps. Mina got on her hands and knees, waving her ass in the air.
"Maybe I can go for another round," said Mina.
"Excellent. The more I have, the better," said Mei.
Mina pushed on the side of her bosom. Another squirt came from her nipple, traveling down the tube into the cups. "Don't drink from those first two. They'll burn your throat. This is the kind of stuff from class. Tsuyu's a big fan of it."
"Perfect," said Mei. "All I've been having is energy drinks and whatever's in the school vending machine. This will be an excellent addition to my workspace. Let's milk you, Ashido." Mei looked at Mina with an expression of curiosity and arousal.
Mei climbed onto the table, pressing her breasts into Mina's back. The sensation of Mei's hard nipples rubbing against her turned Mina on. A gush of milk sprayed from her breasts, coating the entire bottom of the cup in her milk with a single squirt.
Her wet pussy rubbed against Mina's back, her clit itching with a light tingling sensation from the sweat building up. Mina rocked back and forth on the towel-covered lab table, milk spurting from her breasts with increasing intensity. Mina's nipples had become extremely sensitive, torn between the burning of the acid flowing through her pores, the sensitivity of her pink points being tugged by the suction cups, and the pleasant release of Mei squeezing the milk out from her chest.
The next set of cups was about to overflow, but Mei couldn't break away from Mina now. Her clit was hard and quickly approaching orgasm. Mei rubbed her pussy down Mina's back one more time, and squirted onto her skin. The sticky, oily secretions from Mei's pussy dropped onto Mina's back, sliding down her skin and into her butt crack. Mina shivered as the warm, oozing girl cum passed over her anus and towards her own wet pussy.
Mei stepped away from Mina, drops of love juice falling from her pussy and onto the floor of the lab. Mina panted heavily, not quite to orgasm, but extremely close. If anyone touched her, her body would release all of its tension in one go. Mina unhooked the second set of cups, once again preserving them. The suction cups came off Mina's chest with a wet popping sound.
"I know what your weak point is, Ashido," said Mei.
"Where's the cups?" asked Mina. "I'll make a mess of your lab."
"You can't get this messier than it already is," said Mei. "I want to drink the milk of your climax directly. In-to my mouth. I'm sure that's when it tastes the best."
Mei reached for Mina's horns. She rolled the tips around on her fingers. Mina moaned loudly, followed by a shout of orgasm. Her panties became soaked with her orgasm, and milk sprayed from her nipples in a high pressure release. Mei opened her mouth, catching the drops of acid milk on her tongue, swallowing as much as she could hold. With a loud gulp, Mei let out a foul-smelling burp and thanked Mina for her work.
Mina collapsed onto the table, a small stream of acid urine melting through her panties and the towel beneath her. Tiny drops of milk fell from her nipples. Mina let out a blissful sigh, and rolled over on the table. She almost felt like falling asleep.
"If you get acid on your face in a lab, you have to use the shower," said Mei.
"Those aren't supposed to be seductive!" said Mina.
Mina and Mei stood under the lab shower, grabbing each others' butts as a heavy waterfall of semi-cold water splashed on their bodies. They laughed, unsure of what to say, and spent the remaining time in the lab in silence.
A week later, a package arrived for Mina in her dorm room. It was acid-resistant maternity underwear done in the style of her hero costume, with an easy open spot for her acid milk. After double checking that Mineta wasn't peeping on her, Mina tried it on and looked in the mirror in her closet.
"I look sexy," she said. "Way to go, Hatsume!"