Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/13182060.
  Rating:
      Explicit
  Archive Warning:
      Underage
  Category:
      M/M
  Fandom:
      Shingeki_no_Kyojin_|_Attack_on_Titan
  Relationship:
      Armin_Arlert/Eren_Yeager
  Character:
      Armin_Arlert, Eren_Yeager, Grisha_Yeager
  Additional Tags:
      Omega_Verse, Alpha_Eren_Yeager, Omega_Armin_Arlert, Age_Difference,
      Mating_Cycles/In_Heat, Shameless_Smut, Knotting, Possessive_Behavior,
      Possessive_Eren_Yeager, POV_Eren_Yeager, the_ending_has_light_angst, lmao
      who_am_i_kidding_the_ending_is_full_angst, it's_kind_of_an_open_ending
      too_tho, Alpha/Beta/Omega_Dynamics
  Stats:
      Published: 2017-12-28 Words: 2466
****** Temporary Lust, Lasting Sorrow ******
by pinkheichou
Summary
     Armin went into his first heat and Eren wants to help him get through
     it.
     He didn't know, though, what that would do to him.
Notes
     We don't have enough Eremin a/b/o fics and we don't have enough
     Eremin age gap fics...
     So here I am c;
See the end of the work for more notes
Armin’s breath was erratic—too erratic. So Eren placed a flat hand on the
juncture of his chest and throat. “Armin, breath. Please. Don’t forget to
breath.”
The blond’s head shifted to the other side, lips bitten hard it almost drew
blood. Armin moaned as he gushed out a new wave of pheromones.
Eren took that candid smell in, and it drove him to blissful madness.
He looked down at the lean naked body under him, watched how it transpired a
glossy sheen of sweat on the skin, glistening sumptuously.
Eren was kneeling and hovering above him, naked too. His dick was almost fully
hard, just from the sight of Armin’s body in heat and the smell he was encased
in.
Armin had his legs bent and spread them more now, dug his fingers into the
puckered rim of his ass and spread his slick cheeks wider as well. He sobbed,
“Eren. Please. Please, please, please. Fuck me. Put your cock inside. Fuck me.
Give me your knot. Just,” He swallowed, choked on his breath, and Eren had to
remind him to breathe once more, had to keep his head still, eyes locked so
that Armin wouldn’t lose himself during his heat. His first heat. Armin went on
with a quivering bottom lip and glassy eyes, “Just anything. Anything is fine.
But, please, don’t leave me empty. Eren, please. My fingers aren’t enough. I
need… I need something else to fill me. I can’t take it anymore.” At this
point, Armin couldn’t present himself more splayed open for Eren than he was
already doing so right now.
Surely, Eren’s Alpha side was brought to insanity with that.
Armin was his friend, a good friend. He was helping him out, Eren told himself.
And it was at that very moment that he remembered the previous conversation
with his father.
“Armin is in heat?” Eren stunned, looked at his father with incredulous eyes.
Grisha faintly nodded. “Yes, he is. And it’s early for him, actually. Too
early. Armin is only 14. Male omegas go into heat at the age of 16—at the
earliest. Even then, it is more usual for them to hit that point later in their
life.”
“Is that bad? I mean… Armin…”
“It isn’t bad as per se. But, well, I am not allowed to give him any
suppressants because his body is not developed enough to process the
substances. For the time being, I gave him harmless herbal sedatives instead.
However, it won’t do anything against his heat, it’ll just ease off his bodily
functions which have to deal with the effects of a body in high sensitivity and
a feverous sexual drive. This is the first day of Armin’s heat and it is most
likely a bit too much for him. So…”
Eren blinked fast. “You want me to fuck—”
“To take care of Armin, yes.” Grisha held a solid look on Eren, lips pressed
together as he nodded firmly once. “You and Armin aren’t strangers. You two
know each other for long. I’m sure, you, as an Alpha also, would take good care
of him.”
“But dad, I’m an adult. Is that… Is it okay for me to…”
Grisha displayed a small smile. “Don’t worry about that, son. Of course, I’ve
talked to Armin before. You’re the only one who he’s trusting. Armin’s parents
have been informed as well, and their consent – while it is still all about
Armin’s choice – is guaranteed.”
Eren’s gaze wandered to the floor, unfocused.
Grisha tried to encourage him with, “You aren’t that old yet. Early 20 is fine.
For Armin, too.”
“A-And, and what about birth control?”
“He can’t get pregnant. That’s impossible. He shouldn’t have gone into heat in
the first place.” Grisha shrugged and adjusted his glasses on the bridge of his
nose.
Eren met Grisha’s eyes again, a stern glance that softened in the end. “Okay.
All right, I will do it.”
“Good.” The surface of Grisha’s glasses reflected the light as he lowered his
head before he raised it again. “One last thing, though. I hope you know that I
don’t want to force you to do it.”
A little pause where they maintained their mute glances until Eren was the one
to smile genuinely. “I know. I’m doing this because I want to help Armin. If I
can prevent him from being in tight and needy discomfort, then I will do it.”
So here he was, being a witness of Armin’s first heat and also taking care of
it as an Alpha.
Armin mewled, “Eren, please.” Tears began to roll down.
“It’s all right. No need to be desperate anymore. I’m here, okay? I’m here for
you.” Eren lifted one of Armin’s legs to his shoulder and held it there, his
other hand guiding his cock to Armin’s leaking entrance. That Armin had
released a good amount of slick made it only clear how pent-up he was.
Eren rasped out his first moan when his tip pinched inside, engulfed by
tightness and hotness. An amazing feeling that scraped against his restraints.
“Oh my god, Armin. Your ass is sucking me in.”
“Eren, Eren, Eren…” Armin sang in a mantra, and Eren thrust fully into him now.
When Armin looked down on himself and saw how Eren’s gorgeous Alpha cock was
wholly seated inside of him, he revelled in that new  – never known before  –
feeling; his hands pressing on Eren’s lower abdomen. Streams of tears stained
his face as he sobbed Eren’s name over and over again.
Eren cupped one of his wet cheeks, inched his face closer to the other’s,
started to rock into Armin at a steady pace. His cock was enwrapped by Armin’s
ass as much as was possible, was clenched between slick and pliant walls.
The prickling sweet Omega scent intermingled with Eren’s musky Alpha odor,
which oozed out of his pores more prominently because of the presence of an
Omega’s heat. Eren lost himself in it just as Armin was lost in the thrills of
his heat.
Eren picked up his pace, keen to fuck Armin raw with how beseeching Armin was,
praising Eren for having such a great, thick and throbbing cock. It awoke his
feral Alpha instincts and Eren let them take over him.
Right now, Armin looked the prettiest to him. The way he writhed and wound
under Eren’s touches and thrusts fuled Eren with pride he drank in greedily. It
squeezed out a bestial growl from his throat, sounding scathingly sharp.
Yeah, Eren wanted to black everything out and give in to the pleasure of an
Alpha mating with an Omega in heat.
He had to forget, especially after countless attempts of forgetting his dad’s
last words which he had stubbornly rejected to retort to.
“Eren,” Grisha put each of his hands on Eren’s upper arms. His voice was
serious but fond. “I’ve been noticing how your scent would change whenever
Armin was around you.”
Eren had gone into a momentary freeze, blood going stiff and heart clenching.
Looking into his father’s eyes as if he was caught out committing a crime,
Eren’s mind started to spin, the words whirling in his ears, giving him a
headache. The physical ache, though, could not conceal his true emotional
feelings.
And yet, stubbornly, Eren slapped his dad’s arms away with a brisk move. “There
is no meaning behind that.” had been all he had monotonously said to Grisha.
Their talk had ended right there and then, Eren heading for the room Armin had
been stationed in.
The denial… would come back.
It showed itself again; right now, to be specific.
The worst of the worst times for Eren.
Thoughts of ‘Armin, you are so amazing, so gorgeous, so precious.’ and ‘Your
body matches perfectly with mine.’ and ‘You smell so great. You have the most
beautiful fragrance ever.’ abused Eren’s mind ruthlessly, not letting him any
room for denial or reluctance.
Eren – his Alpha – longed for the one it desired.
When Eren was already fucking hard into Armin, coaxing out shameless and vocal
moans out of the other, he picked him up, thrust into him while Armin was sat
on his lap until he would start fucking himself on his cock.
Heat and sweat blazing under his skin, Eren was clouded by the sensation of
having an Omega – Armin – by his side. Armin wasn’t his first Omega. But surely
this felt more special than all the other times he had had sex with an Omega.
Eren couldn’t hold back anymore.
The craving flooded him.
Armin cried out lewdly on his shoulder. “Ah, E-Eren… your—”
Eren’s pointer finger rubbed over Armin’s scent gland on his neck, causing for
Armin to startle at first and scream moans to it. “Shhh, it’s fine, Armin, it’s
fine.”
Armin grabbed the back of his shoulders hard, pulled his nails down his skin.
“Your scent, Eren… so good. Your dick… ‘s so good. Everything feels so good.”
Eren groaned senselessly.
A single word.
Mi—
No, he thought. Couldn’t happen. Couldn’t be, never could.
Croons vibrated in the inner of his throat as he brushed Armin’s hair away from
his neck while Armin would bounce adamantly on his cock, ass wet and cock
dribbling ounces of pre-come. Eren set his lips next to Armin’s scent gland and
had to use all of his self-control in order to not mar his skin open with his
teeth.
He sucked on the skin instead, sucked hard, tongued the parts that were circled
by his mouth.
For now, you are mine, Armin.
There was it.
“Fuck…” Eren let go of him, gripped Armin’s hips and gyrated his own ones
aggressively, pounding into Armin with fervor. He didn’t lose eye contact with
the other, stretched his own throat, tipped his head back a bit so that he
wouldn’t miss a single reaction mirrored on Armin’s face.
Brows creased from eagerness, lips mauled by teeth, eyes dilated, and Eren
freed his yearning from its cage.
You’re here with me now, Armin. You’re mine right now. Mine, mine, mine.
But I want you to be mine forever!
Eren closed his eyes as these particular thoughts, his innermost desire, ate
him out from the inside.
By now, his previous statement of only wanting to help Armin sounded grotesque
to him.
Eren felt pathetic. He was pathetic, so he thought.
He could never… Armin…
“Eren…” Armin brought a part of Eren back to reality, the other part wallowed
in bittersweet void still, “Your knot, please. Eren, I—”
“I’m almost, hngh, there. Almost there, Armin.” Eren grunted hot breath into
the crook of Armin’s neck. His nose nuzzled Armin’s scent gland again. His neck
looked so pretty. So smooth. So empty without a mark.
And it was then that the idea of wanting to bite into Armin’s neck, to claim it
and scratch other parts open as well, to itch his possession into Armin’s body
with teeth and nails, sounded so great. So perfect. He would lick and suck on
every bloody spot. And he would kiss every mark pretty.
The mating mark that would form on Armin’s neck would become something holy to
Eren. And Eren would kiss every part that was Armin, all the while whispering
how Armin was his. Mine, mine, mine.
Please be mine.
Eren emptied his shot inside Armin, blessing him with the feeling of getting
filled up before the base of Eren’s cock started to swell, gradually locking
Armin’s body with his. During that process, Armin would come as well, shouting
into the night, eyes rolling back as his first orgasm ever and his first heat
ever overwhelmed him in form of the feeling of utter lust.
The sight of Armin ascending to an ecstatic state – ascending to
ecstasy because of him – was a pure blessing to Eren. He kissed Armin’s chest
once, lips coming into touch with sweat that was rich in an Omega’s heat and
scent, as he cautiously lowered Armin to the bed while the knot lasted for a
little while longer.
They lay like that on the bed, facing each other. Armin was mainly trying to
catch his breath while Eren would finger the crack of Armin’s ass, though not
taking his eyes off of the other.
Armin was too wrung out to think properly. “Eren?”
“Yeah?” Eren breathed hoarsely.
“Eren, I— hahhh,” Eren’s knot deflated and with that, his spurt leaked from
Armin’s ass, giving Armin a giddy feeling. But it still felt good in some way.
“Eren…”
“It’s okay,” Eren tugged a few strands behind Armin’s ear, endearingly, “You
don’t have to talk or think right now. Have a rest.”
“Hmhm.” Armin hummed, eyes already shut as he pulled his knees up and snuggled
into Eren’s side, cuddling his arm. While Armin was, technically speaking,
still in heat, the current moment kind of counted more as an “aftermath” of it.
But of course, especially now, Armin’s first instincts would tell him to stay
close to an Alpha—the one you spent your heat with.
Eren’s face nuzzled into Armin’s hair, wanted to be selfish for this one
second, and so he breathed in Armin’s scent. It smelled so good. Armin smelled
so good, it took Eren’s breath away.
At the same time it ached him so much—so, so, so much. The pain numbed him to
the point that he didn’t sense when it was that Grisha had entered the room.
“Eren.” he called out calmly.
Eren turned around, slowly, feeling as if his soul was ripping itself out of
his body, his primal instincts a howling chaos. By the time he looked up to his
father, his sight had already gone blurry, a flow of tears pouring down his
face, stealthily.
Grisha would like to be spared from the sight of his own son crying in pain,
but at the same time he understood. He knew.
What else could be a reason for an Alpha’s altered scent when being around an
Omega other than the Omega being dear and significant to them?, Grisha sighed
lowly. Deep down, he wished for his son to come to terms with himself. To not
fight with his irrational, self-loathing side anymore.
To accept and appreciate what he actually deserved.
But Eren was far from that.
“Dad…” he croaked, every intake of breath stung in his chest.
Eren shouldn’t have agreed to this. He shouldn’t have done this in the first
place. He was at own fault for having inflicted pain on himself.
What else could hurt an Alpha more than the scent and presence of an Omega he
wanted but couldn’t have; couldn’t claim for himself.
Eren wanted Armin.
Mine.
Ever since he first laid eyes on him.
Ever since then…
Mine, mine, mine. Please.
Ever since then, Eren had been infatuated.
End Notes
     There are a few things in this fic that are open to interpretation
     ;)))
     tumblr: pinkheichou
Please drop_by_the_archive_and_comment to let the author know if you enjoyed
their work!