Izuku stuttered incoherently as he stared up into 13's golden brown eyes. The rest of her features becoming clear as Izuku's head stopped spinning. Her hair starting blond at the roots but shifting to black further down as it framed her adorable round face.

Or rather it would be adorable if she weren't staring at him with ravenous hunger and rage.

Izuku then squeaked as 13 began chuckling evilly.

"Finally... after having to listen to you going at it with every other girl and her mother all day long... after hearing just how good you made them feel while not even getting the time of day from my cheating ex, who doesn't even realize I dumped his ass yet!... Now I finally have you all to myself..." 13 monologued while staring at Izuku as if he were a rare cut of meat. She even licked her lips as she ran her had over his abs.

"You won't be needing this though" she said and, much to Izuku surprised and horror, showed a level of mastery over her quirk that he'd never seen before, as she used it to disintegrate his meager attempt at replicating cloths after parting ways with the class B girls.

Izuku swallowed the lump in his throat as 13 loomed over him.

"N-now sensei..." Izuku started, only to yelp as 13 suddenly came eye to eye with him. As in literally centimeters apart.

"What! Going to try and talk your way out of this? Be all heroic and try to preserve my honor or whatever!?" she challenged with a deranged tone.

"No..." she continued quietly as she pinned Izuku's shoulders down.

"It's your fault I've been so worked up all day with no time to relieve myself. All the while listening to every single girl you go after screaming in ecstasy...EVERY... TIME... without fail... sometimes for HOURS! It's your fault that I've had the perfect excuse to finally get some good action after a year with my small dicked, cheating ex being nothing but a disappointment... only to hold myself back because of stupid concepts like morals and common decency..." she paused as her thoughts went to the man in question. Her breathing becoming ragged as her rage built and her nails started to dig into Izuku's skin.

"That bastard..." she muttered before locking eyes with Izuku again.

"Midoriya... you are going to give me the best fuck of my life this instant! And you're going to show that son of a bitch what a real man can do..." 13 said with a feral grin.

Izuku began shaking in fear a little. Though more for 13 than himself. He'd never seen or heard 13 like this before. He'd definitely never heard her using foul language this much... or ever for that matter...

13 then sat up on him and Izuku's eyes bugged out. He'd seen her with her helmet down once or twice before, but never out of her suit, so he was dumbstruck by how petite she was.

She was so incredibly slim, and flat as a board, front and back.

She could have almost passed for androgynous if not for her face and the fact he knew for sure she was a woman. Both from foreknowledge and her womanhood pressed and leaking against his lower abs.

Or at least they were until she lifted herself up and Izuku gulped as he saw her small entrance flexing desperately. He could tell just from looking that she was going to be extremely tight.

"W-wait-" Izuku tried to intervene before 13 could hurt herself, but she slammed herself down before he could stop her and make her take it slowly.

"GAHAAAAAHAHA!!!" 13 cried out as Izuku completely filled her incredibly tight womanhood. Lucky for her, she was so wet that Izuku slid in easily, in spite of how much she was clenching down on him.

Unfortunately, and much to the surprise of the both of them. 13 couldn't fit all of Izuku inside her, and they both looked down in shock at where they were joined, as Izuku's diku pressed against 13's cervix and yet he still had a few inches left.

"Oooohhhhh! Fuck yes... Finally a real dick that I can actually feel!" 13 moaned in pleasure, excitement and relief.

Izuku was growing more and more concerned for 13 though. Both because of how desperate and far she was willing to go. But he couldn't help but wander just how small and incompetent her ex was if she was this tight and he couldn't make her feel anything at all.

While Izuku was pondering that though, 13 began forcing her hips up and down. Fighting the grip of her own womanhood as she tried to take more of Izuku inside each time.

"Oh fuuuuuck..." it was Izuku who moaned this time as 13 yelled and cried out. He had never had his little Deku in such a vice grip before, and yet 13 had been so worked up and desperate that she was practically drenched downstairs.

With a particularly hard thrust, 13 arched her back and threw her head back in a silent cry as she finally took Izuku just a little bit deeper. His tip penetrating her womb a little and letting her cervix wrap around and squeeze his head.

Izuku could only grunt as his fingers dug into the medical bed and his eyes rolled back in his head. He eventually managed to pry his right hand free and send it forward to try and grab 13's hip. Izuku was shocked when his hand met her lower belly though and he felt a bulge.

Izuku lifted his head to stare dumbfounded at the outline of his manhood under 13's skin.

"How the hell can anyone be so small that you don't feel anything!?" Izuku couldn't stop himself from yelling in disbelief as 13 screamed in orgasm.

"Oooohhh fuuucking finally! I haven't orgasmed properly in nearly a year!" 13 exclaimed as she shook on top of her student.

Something inside Izuku seamed to snap after hearing that though.

"AAAAAAAAHHHHHHHH!!!!!" 13 suddenly screamed out and arched her back further as Izuku lifted his hips while pulling down on 13's, forcing his manhood all the way through and causing her skin to distend outward where he was hitting the back of her uterus.

He wasn't quite sure why but hearing and feeling how neglected 13 was, sent him over the edge. Next thing ether of them knew, Izuku began thrusting up into her from below, causing 13 to cry out in utter bliss as she orgasmed near constantly on him.

"Oooohhhhh FUCK YEEEEEEESSSSSS!!!!" 13 screamed before going boneless from the pleasure and Izuku had to sit up to support her as he smashed her unmercifully.

13's face was a mess. Her eyes rolled up in her head and her mouth hanging open in perpetual cries of ecstasy until Izuku gently grabbed the back of her head and guided her into a kiss.

After a few moments, 13 finally adjusted to having proper sex for the first time in a year, instead of whatever her ex had been attempting and she stopped orgasming constantly. She then began kissing Izuku back as she started bounced on her own again as she clung to Izuku to hold herself up.

With her now in control of her own body again, Izuku was free to send his hands elsewhere. Feeling up every part of her body. Even her flat chest and rear.

13 managed to keep the lip lock up a bit longer before having to throw her head back in another orgasmic scream.

Izuku took the opportunity to lean forward and latch onto her right nipple. Sucking and licking at it until it was erect before switching to the other and giving it the same treatment.

13 held Izuku's head to her chest as she moaned.

"Oh fuck yes! He never touched my chest, even though it's my most sensitive place!" She moaned out only to then yelp as Izuku sucked and nibbled harder in response while sending his hand up to pinch her other nipple.

13 screamed her way through yet another orgasm in response. By this pint Izuku's pelvis and the bed were both soaked with her juices.

Then 13 tensed up and her nails dug into Izuku's scalp as she looked to see her flat chest begin to grow before spraying milk.

13 started to go boneless again as her extra sensitive breasts became even more so. Her pleasure induced clenching causing milk to spray out with even more force, leading to more pleasure as Izuku continued to suck and work her now defined breasts.

They were still small but they were unmistakable and her ass grew a little more defined as well, as her hips widened a little.

Her hips widening also caused her birth canal to open up a little and gave Izuku a little more room to thrust faster, causing 13 to fall on her back as Izuku finally released her breast and scooted back so she could lay on the mattress as he continued to thrust into her.

13 cried out incoherently as her lower belly destined with each thrust Izuku gave her. His hands planted firmly on her breasts to hold himself up and work her squirting tits in his hands, sending 13 further into orgasmic bliss as she trembled underneath him.

"Aaahhhh!!! Please Midoriya! Please cum in me! Gaaahhh!!! Please make me yours! Please make me feel this good every day for the rest of my life!!! EEEAAAAAAAHHHHHHH!!!" 13 begged before screaming out in pleasure as Izuku squeezed her breasts harder, sending milk shooting up.

"Sensei... I promise, you'll never be so neglected ever again..." Izuku promised, giving one last thrust while using her breasts as handles to thrust deeper as he came inside her.

13's eyes bugged out and her mouth hung open in a silent scream as she felt the liquid heat of Izuku's release filling her. Then she looked down and watched her lower belly bloat a little with Izuku's cum as her cervix clenched down tightly on Izuku's manhood and allowed nothing to escape.

13's legs then shot outward and her whole body trembled in a mind melting climax as she screamed.

13 then went limp as Izuku hunched over as smoke briefly emanated from him and he focused on holding himself up as he recovered.

"Ok... that was... different..." he muttered as he came back to his senses. He'd felt compelled by his quirk before, but this time was a bit different. The usual compulsion to breed was there but part of his conscious and rational mind had wanted to smash 13's brains out after he realized just how badly she had been neglected.

...

He also felt a sense of pride, having so thoroughly satisfied her, much to his shame.

"This quirk is corrupting me..." Izuku deadpanned as he unconsciously continued to lightly squeeze 13's breasts as he pondered.

"Good..."

Izuku was pulled back to reality with a yelp as 13 spoke quietly before suddenly lunging up and pushing Izuku back to his back.

"Oh no..." Izuku muttered as he realized 13 wasn't done yet. Something that he should have expected in hindsight, considering she'd been forced to listen to and clean up after Izuku's sexual escapades all day, combined with a year of nothing but disappointment from her ex.

"Oh yes..." 13 replied before turning around and slamming down on Izuku's still erect manhood again and she started bouncing quickly and violently, causing her breasts to bounce and squirt more as her pleasure built again.

Izuku just sighed as he accepted his situation.

"I'm getting way too used to this" he thought as he took hold of 13's hips to help match pace with her as he began thrusting up.

Once they were in sync, Izuku sat up and reached around to work her sensitive breasts some more and then leaned around to suck on her right one as she bounced aggressively on Izuku.

13 screamed as she felt Izuku drink from her sensitive breast while he pinched and twisted her other nipple and she fell back against his chest. Izuku then wrapped his arms around her and hugged her close while still squeezing her breasts as he laid back down, taking 13 with him and letting her lay on his chest as he thrust up into her. Her belly bulging each time.

Izuku made sure to pull back out a little so he wasn't all the way inside though. After all, her womb was about to be occupied.

And no soon did he pull, then 13 screamed as her belly began to grow and grow, looking far to massive for her small frame by the time it stopped.

Izuku continued to thrust up into 13 a bit longer, bringing her to one final, explosive orgasm along with him as he finally finished and 13's voice finally gave out before she passed out on top of him.

Izuku panted for breath as he hugged 13 to his chest. Her increased weight proving a little uncomfortable, but he was more than willing to endure it for 13 and their children.

Speaking of which, Izuku let his right hand wander down to rub 13's belly and feel the activity inside.

"11... I hope they're not too much for her..." Izuku muttered with concern as he couldn't avoid the clear discrepancy between 13's small frame resting against his body, and her now oversized belly. Though really it could have been much worse given how strong Izuku's quirk was becoming and how desperate 13 was.

Izuku sighed as his mind drifted to another issue though.

"How am I gonna tell Snipeand the others that 13 can't help anymore" he muttered with sympathy towards the overworked hero.