Chapter Text
There are many reasons for omegas to nest, all related to childbearing. During heat, omegas build their nests as shelter whether they’re mated or not. It’s a basic instinct that makes omegas feel safer.
Nests vary from person to person. Some nests are bigger, some smaller, some even rarely nest. Some prefer to fill them with snacks. Omegas with pups might prefer adding their pups’ scent, while mated omegas tend to prefer their mates’ clothing to ward off predators.
While this is a natural instinct, heats and secondary behaviors can be repressed with the help of inhibitors.
Bruce Wayne, aka the freaking Batman, knows all of this very well because, believe it or not, he’s an omega himself. And he’s not ashamed of it; it’s inconvenient, sure, but it’s not like he’s trying to hide it. In fact, Brucie Wayne is Gotham’s most chased-after omega. If people believe Batman’s an alpha though, he won’t bother correcting them and risk his identity.
The majority of the League, for instance, think he’s an alpha, or at the very least a very dominant beta. In his defense, no one ever asked him, and very few people know the Batman is an omega: Alfred, Dick, Clark, and Diana… after all, she’s too smart to mistake his heat for a rut like most people do.
Otherwise people don’t take notice, since Batman doesn’t take breaks often. Crime doesn’t wait for him to lay down, and with the best inhibitors money can buy, he doesn’t need to. Even if he still gets his heats, they are mellowed down enough that he can just burn it out fighting thugs. So it’s fine, really; he forgets about it for the most part.
Nesting isn’t even an issue, he’s too tired most of the time to prepare anything, plus he just doesn’t want to. When he adopted Dick, though, it became like a little itch in his skin, nothing he can’t ignore, but Alfred of course picked up on it. And if, right before his heat, some of Dick’s pillows made their way into Bruce’s bed? Well, he never commented on it. But that’s it; his nesting is basically nonexistent, his heats are under control, and if need be he can deal with them by himself. As much as he likes to make people believe, he would rather die than get an unknown alpha in his bed. Being fair, he’d probably choke any alpha that posed even a slight threat. It’s for their protection, really.
His second gender is nothing more than a title. Dr. Thompkins differs though, saying that if he continues to abuse his inhibitors throughout his heats, they will eventually start losing effectiveness. But he can’t take the luxury of sick days. He’s Batman! He’ll just get better inhibitors if needed.
So he doesn’t think about it. The worst that could happen is some drug dealer getting a worse beating than usual during his heat, and he’ll just go get a stronger dose.
***
At first, it starts with small things, trinkets really, so he doesn’t give them much thought: Dick’s mask, for instance. He’ll have to lecture him about leaving stuff lying around. Alfred’s novel: maybe if he reads it he’ll understand why the old man loves it so much. But it seems like he keeps forgetting to give them back… So stuff continues to disappear around the manor.
Until one day it’s not only the manor, but the Watchtower or, to be specific, one blue-and-red hero that falls victim to this series of disappearances.
“B! Have you seen my glasses?” Superman asked, lifting a sofa over his head. “I know I left them around here somewhere…”
Bruce doesn’t answer, instead choosing to give Clark his best poker face, which succeeds in making Clark increasingly nervous.
“I’m sorry? It’s just… I know they were damaged, but I figured I could fix them, and um-”
“I have them,” Bruce cut through. Maybe honesty was the best strategy. “I want to run some tests. I’ll hand them back to you in a few hours.”
“Oh no, don’t worry! They were probably beyond repair either way. I’ll just make some new ones at the Fortress,” Clark said sheepishly. “Anything to help.” But before leaving, there was something else: “Oh, by the way, have you seen my Superman tie?”
“Stop leaving civilian clothing around the Watchtower,” Bruce grunts. Clark doesn’t need to know, and that tie is an abomination.
“Right, sorry.”
Technically, Bruce did think about running tests on those hypno-glasses; he just never got around to it, and somehow they made their way into his nightstand… along with a piece of cloth from Superman’s cape, the tie, and even a Daily Planet pen. But everything has a reason; he just doesn’t feel the need to share these reasons.
This goes on until Alfred decides it’s time to address the matter.
“Sir, if I may ask, is there any specific reason you don’t wish for me to enter your bedroom?” Alfred asked during dinner on day five since the disappearances started.
“It’s called privacy,” Grumbled Bruce in between bites.
“I see…” As skeptical as possible, and after a moment, he decided to just be straightforward: “Sir, I assure you, there is nothing to be ashamed of if you’re nesting. We’d be happy to-“
He doesn’t nest; he never has. “I’m not nesting, I don’t-“
“I know you have been collecting Master Dick’s and my personal belongings, sir. We don’t mind in the slightest,” said Alfred with a gleam in his eye. “If there is anything you need, please let us know and we’ll be happy to provide it.” The sincerity in his tone made Bruce speechless, so he decided to take another bite of his food in response. “Oh, but please do feel free to take anything you need in exchange for my book. I’m dying to know whether the protagonist made it in time for the wedding…”
Right, so maybe he had been taking a few minuscule things here and there, but he’s not nesting. He’s just… taking mementos? It’s a weak excuse even for himself, but he’s never nested, and he’s grown; he knows when his heat is approaching.
***
He, in fact, did not know what his heat looked like after years of inhibitor-suppressed heats. And with his heat just a couple days away, things started to get more obvious… except to Clark, who was still grieving his lost pen.
“Superman,” Batman called one afternoon as he entered the Watchtower’s lounge area, where Clark and Diana were currently having coffee.
“B! Everything okay?” Clark said, a smile so bright you might think the sun itself had an offspring.
“You said you’d help. I need something… clothing, to run some tests.” He masked the insecurity in his tone extremely well, but not enough to escape Diana’s attention.
“Any… specifics?” Clark asked, confused. “Any hints on what we’re testing?”
“Just regular tests. I need your clothes- just whatever you have.”
“Suure… Alright, I’ve got some clean-“
“Used! I need- to check for bodily fluids.” Bruce tries to say it as calmly as possible, but his heart betrays him, alarming Clark in return, who, faster than the speed of light, returns with a handful of clothing.
“I-I used it this morning, is this-“ Before he can finish his question, Batman is already out of the lounge with Clark’s clothes and on his way to the teleports, leaving an anxious Superman behind.
“Diana, what type of tests is he running? Am I dying?” he says with puppy eyes, to which Diana, who watched the entire interaction, can only respond by bursting into laughter.