AUTHOR'S NOTE: I can't resist mpreg!Cas or births, so I eagerly filled the following prompt from the LJ SPN Kink comm:
"When Cas gets pregnant with twins, an excited Jack researches everything there is to know about pregnancy. Of course, he's the only one with Cas when his water breaks.
Jack tries his best to comfort a clearly terrified, hurting Cas and helps deliver his siblings."
And somehow, eager and excited Jack feels like it's edging toward dark and possessive Jack which was not how I intended it, but I'm pretty sure it's not noticeable unless you're looking for it; I'm just paranoid.
Jack still didn't have a firm grasp on his powers. It didn't help that no one knew what powers a nephilim could have. Castiel did his best to train him on the basic powers that most angel's had, and how to control his grace which helped with a lot of things, but Jack still felt like the little control he'd learned over his powers was tenuous at best.
He could still help with research though, and he dove into that with as much enthusiasm as Sam which Dean had teased the boy about until, Jack suspected, Castiel or Sam (likely both) had told him to cut it out because it made Jack happy to help. Whenever Sam and Dean left on a case together, Jack stayed behind with Castiel to safely practice using his powers, but also to research and aid the brothers from the safety of the bunker.
When Sam and Castiel (who had been together since before Jack was even born, he'd been told) announced that the angel was pregnant, it was with this ferocity that the nephilim dove into researching pregnancy and labor & delivery. His new brother or sister would be just like him, and he wanted to do everything he could to help Castiel deliver a healthy baby. Unlike his own birth, there was no threat of Castiel dying because of this (a fact that relieved him; he didn't know what he'd do if he lost his father), but Jack was so excited to have someone else like him, he wanted to make sure everything went as smoothly as possible.
Then Castiel announced he could feel two different grace signatures beneath his own. The announcement that he'd have two new siblings solidified Jack's resolve to help Castiel any way he could. At first, it was hard because Sam, as Castiel's partner and the father of the twins, was the angel's go-to for support. Jack felt like his father didn't need his help when he had Sam around. Despite his wariness of leaving Castiel alone, Sam agreed to continue hunting with Dean, and now the time Jack spent alone with his father became even more special.
Instead of Sam running to the bathroom behind Castiel, it was Jack. It who got to rub his back when he vomited, moaning in discomfort. Jack was the one that got to fetch him a cloth to wipe his face and a glass of water to rinse his mouth.
When the angel got hungry (because eating supplemented his grace, which was now supporting his body and carrying a pregnancy), Jack made him whatever he wanted if it wasn't too complicated. He even brought it out with a big smile even if it wasn't something he thought would taste any good. Not that Castiel himself could really taste it; everything still tasted like molecules to him.
When his belly grew large and round and started making his back and hips ache, Jack volunteered to massage them, his bony fingers perfect for digging into tight muscle and loosening knots. He'd grin proudly behind his father's back when the angel would slump forward with a relieved sound somewhere between a sigh and a moan.
Jack loved the time he got to spend alone with his father, providing his help, and making Castiel happy and comfortable.
So it was almost right that Castiel went into labor when the brothers were halfway across the country on a hunt that they knew needed to be done but hadn't been able to pass on to any other hunters, leaving the pregnant angel with Jack. Because Jack knew what to do. Not just to hold Castiel's hand and breathe with him. Jack knew everything, right down to how one was supposed to hold the infant as it was delivered and how to tie off and cut the umbilical cord. He knew that he was supposed to check the baby's airways and immediately put the baby on its mother's (or, father's, as this case may be) abdomen for bonding.
It had started like any other day when the angel and nephilim were alone. Throughout the day, Jack had been keenly aware of how Castiel seemed more quiet and subdued, attention seeming to focus internally rather than on Jack's training. After only an hour, Castiel had quietly said that he needed to stop for the day and wanted to lie down. Jack didn't miss the way the angel's hand repeatedly rubbed little circles into the side of his belly, but he assumed it was because the twins didn't have much room to share between them.
"I'm sorry, Jack," Castiel apologized, mistaking Jack's concern for disappointment that he'd had to cut training short. "I'm just not feeling well today."
"Is it your back or hips again?" Jack asked eagerly. If it was something he could fix, his father wouldn't have to leave him. "I can help like I always do when Sam's not here."
Castiel smiled sadly and shook his head. "I appreciate all your help, but I'd rather just go lie down this time."
Any disappointment Jack may have felt at the refusal of help morphed into concern the moment Castiel pushed himself to his feet and immediately leaned forward on his braced palms with a wince and a groan that wasn't the usual sound of discomfort he made when his body ached. As Jack watched, Castiel's breath picked up and he moved one hand to cradle the underside of his belly with a whimper. Then he noticed the dark patch forming in the gray sweatpants Castiel had borrowed from Sam, the darker gray color that indicated something wet streaking down his thighs.
"Your water broke," he said simply, flicking his eyes from the wet patch up to Castiel's face which was still scrunched in pain.
Castiel only nodded, breathing deeply and somewhat erratically, eyes focused on the table. When he finally blew out a long breath and his body relaxed, Jack sprang into action. Though he reminded himself that he had to remain calm for Castiel. He didn't want his father to mistake his eagerness to help for worry about the situation. It was his job to keep Castiel calm until Sam and Dean came home, or until his siblings were born – whichever came first.
"You need to change and lie down," he said, rising and wrapping an arm around his father's waist and using his other hand to gently grasp Castiel's wrist to put the angel's arm over his shoulder, silently urging his father to lean into him.
Castiel stared dumbly at him for a moment before allowing Jack to lead him out of the library and toward the bedroom he shared with Sam. Once inside, he slipped out from under his father's arm and went to the dresser to find a clean pair of sweatpants. When he turned around and Castiel was staring at him, he frowned in concern.
"Do you need help getting them off?" he asked as he laid the clean pair on the bed.
Castiel cleared his throat then shook his head. "No. Thank you, Jack. I've got it."
Jack nodded. "Okay. I'll get a washcloth so you can clean up and then I'll take a towel to the library to check for any puddles. Was there a lot, do you think?"
"I…" Castiel shook his head. "No, it wasn't a lot. But I appreciate your willingness to clean it up."
Jack beamed then hurried from the room to do as he said. He dropped off a washcloth to Castiel then took a towel to the library and wiped up the water from the floor, pleased to note that it was clear and odorless like it should be. When he finished, he hurried back to Castiel, finding him using the edge of the nightstand to lower himself onto the edge of the bed. Jack could clearly read worry on his father's face and knew it was because the angel was in labor without his partner there. Even if they did alert Sam and Dean as soon as possible, there was no guarantee the hunters would make it home in time.
"I need to call Sam," Castiel mumbled as if reading Jack's thoughts, both hands massing his belly.
"I'll do it," Jack volunteered. "You should lie down and rest. I'll lie with you if you want me to when I'm done."
Castiel frowned at him, clearly surprised by the offer, then nodded. "Alright. Thank you."
"You're welcome," Jack said before turning and heading back into the library where they'd abandoned their phones in the commotion. He snatched his from the table and confidently scrolled down to Sam's name and tapped call.
"Hey, Jack," Sam greeted after a few rings. "How's everything going?"
"Good," Jack replied with a nod he knew Sam couldn't see. He kept his voice calm and steady as he said, "Castiel is in labor. His water broke in the library ten minutes ago. I helped him clean up and lie down."
"What? How many contractions has he had in that time?" Sam asked, tone just this side of panicked.
"Just the one," confirmed Jack. "I'll keep track, and I'll take good care of him, Sam, I promise."
"Yeah," Sam huffed, a sound Jack knew meant the hunter was processing. "Yeah, thanks, Jack. We'll head that way now, try to make it home in time."
"I know how to deliver the twins," Jack announced. "I researched. I can do it if you're not home in time. I'll take really good care of them," Jack promised more firmly, knowing Sam would know he meant Castiel and the twins.
"I know you will, Jack. I'm proud of you, buddy," Sam said, the praise making Jack beam with pride. "Call me if you need help or if Cas wants me or if something happens."
"I will," Jack promised before hanging up and pocketing his phone and Castiel's then hurrying back to the bedroom.
He found Castiel on his hands and knees, leaning into the stacked pillows and whining through what Jack knew was a contraction.
"Cas?" he asked as he steadily approached the bed and sat on the edge beside his father, making sure to keep calm.
Castiel buried his face in his arms against the pillows and moaned long and low as he rocked his hips from side to side as if he could move away from the pain. Jack bit his lip in thought then remembered what he'd read about how labor for human women opened up the hips which caused pain, and how pressing in on them countered that. Taking a chance, he got up on the bed to kneel behind his father and planted his hands on Castiel's hips then pressed in firmly. Castiel groaned but stopped trying to move and his breathing became more controlled, so Jack didn't back away. After a few seconds, Castiel blew out a breath and relaxed, so Jack tentatively removed his hands. When it seemed like Castiel was okay, the nephilim shifted to sit Indian style on the other side of the bed to watch his father.
"Did that help?" he asked quietly because Castiel had his eyes closed.
The seraph nodded where he lay against the pillows. "Yes, thank you. How did you know that would help?"
Jack shrugged even though Castiel couldn't see. "Same way I knew how to massage your back or hips or rub your back when you got sick. Ever since you told us you were pregnant, I've been researching everything I could think of to help you feel better. And I researched what to do for you while you were in labor. When I noticed you were rocking like your hips hurt, I remembered that pressing on them helps. It's called counter pressure."
Castiel opened his eyes which crinkled as he smiled at his son, reaching over to brush back Jack's hair then gently urging him forward as he sat up to pull his son into a hug. "You're going to make a wonderful big brother, Jack. You're very thoughtful and kind and loving."
Jack carefully wrapped his arms around his father in return, smiling brightly. "I called Sam," he said as they parted and Castiel arranged himself back on his knees leaning forward on the pillows. "They're on their way back. He said to call him if I need help or if you want him. You should try to sleep," he said when he saw Castiel's eyes fluttering closed again. Like eating, Castiel had started sleeping partway through his pregnancy to ease the burden on his grace.
Castiel only hummed in vague agreement, clearly already beginning to doze. Deciding to let his father sleep, Jack used his phone to call Castiel's, putting them both on speaker and left the seraph's phone on the nightstand as he took his with him, using the call as a makeshift walkie-tallkie. He listened carefully as he cleaned up the materials used for their lesson in the library and took their lunch dishes to the kitchen. As he put them in the sink, he debated whether he wanted to take the time to wash what they'd used or leave them so he could be more ready to rush back to his father's side. The reassuring sound of calm snoring coming through the phone told him Castiel was okay, so he ran warm, soapy water to do the dishes.
When he was almost finished, he heard Castiel shifting and thought he heard a whimper. Just as he paused to listen carefully, towel held between two damp hands, Castiel called his name twice, leaving barely a moment after the first before calling out again. At the panicked tone, Jack hastily tossed the towel on the counter, snatched up his phone, and tore off down the hall.
"I'm here," he said as he slid into the room then hurried to the bed to take the hand Castiel threw in his direction, barely wincing as the seraph squeezed. If he were human, he was sure his fingers would be broken, but he didn't care. "How can I help?"
"Stay," Castiel groaned, rocking back and forth against the pillows with a whimper.
"I won't leave again," Jack promised, using his free hand to rub firmly into Castiel's lower back. When the gesture had Castiel's movements ceasing and the angel's breathing under control, Jack counted that as another win and internally beamed at himself.
When Castiel's grip and whole body relaxed, Jack carefully extricated his hand, but the action made Castiel immediately snap fearful eyes up toward him, so he kept a hand on his father's back as he climbed back up onto the bed and around him to his other side.
"Not going anywhere, Castiel," he promised again.
The seraph nodded against the pillow then closed his eyes with a sigh, hand dipping down to rub at his belly.
They passed a couple of hours this way, but after a handful of contractions, nothing Jack did helped keep Castiel calm and in control anymore. Through a particularly harsh contraction, Castiel had snarled and batted his hand away with a snapped demand to "stop touching me" which made Jack wilt with the rejection and the feeling of helplessness that followed as he watched his father moan and rock and grip the pillow so tightly Jack thought it would tear. The feeling of inadequacy intensified when Castiel whimpered that he wanted Sam. When it passed and Castiel had caught his breath, he tentatively reached a hand out to grasp one of Jack's and apologized for yelling at him, promising he hadn't meant to hurt the boy's feelings. Jack readily accepted the apology; he knew his father hadn't meant to snap at him.
After a moment of silence, Castiel complained that he was hot, so Jack helped him up to undress. The seraph hesitated, knowing it was improper for a child to see his father nude – even if they weren't the conventional human father and son. But Jack gently coaxed him into undressing, explaining that it wasn't likely Sam and Dean would make it home in time and that Jack was going to see his father's intimate bits to deliver his siblings anyway.
"I don't think it'll be long," Castiel murmured as Jack helped him recline against the pillows and pulled the sheet over his lower half for modesty even though that would hardly matter later. "One of them feels very low..."
"Do you want me to check?" Jack asked. "I know how."
Castiel shook his head. "No, just let it happen. They'll come when they're ready."
So they passed several more contractions like this, Castiel grasping Jack's hand with one of his own while the other clutched his belly through each. Jack murmured praises to his father while the seraph panted and moaned and whimpered. After a time, it seemed like each contraction seemed longer with less time between, one melting into the next and giving Castiel no time to rest between each one. During one such contraction, Castiel stopped panting and curled forward with a scrunched up face, his grip on Jack's hand tightening.
"Castiel?" Jack asked, wiggling closer to his father's lower half because he was almost positive Castiel was pushing though the nephilim didn't let go of his hand or look away from his face. "Are you pushing now?"
Castiel nodded sharply, grip tightening on Jack's hand in a silent request for him not to move away. After a few seconds, he released his held breath with a groan as he fell back against the pillow, chest heaving.
"I… I can't," he whimpered, voice taking on that frightened tone that made Jack's heart clench. "Sam's not here. He's supposed to be here, not on some stupid hunt!"
"Hey," Jack said softly, shifting to lean over his father so the seraph was forced to meet his eyes. He squeezed the hand in his. "I'm sorry Sam's not here, but I don't think you can make the twins wait. And I know it's not the same, but I'm here. I'm here, and I know what to do, I swear. I can help. You can do this, Castiel."
Castiel stared at him, unsure, for a moment then nodded and released his hand, giving him a gentle nudge. "Wash your hands. Get what you need. Hurry."
Jack nodded and ran from the room to the bathroom to wash his hands and gather a couple of towels and a basin of warm water. He took those to the bedroom, hesitating when he saw Castiel curled forward and pushing again, but the angel waved him off and breathlessly assured his son he was fine. So Jack hurried out one last time to the infirmary to fetch the kit the Winchesters had put together for the birth. It contained sterilized scissors and thread, clamps, a bulb syringe to suction the babies' airways with, gloves, and any other little thing they'd thought might be necessary during delivery.
When Jack returned with the kit, Castiel was pushing still (or again?), so the nephilim snatched up the two baby blankets that had been laid out on the chair in the corner, leaving them beside his father to use for the twins then set up the kit on the bed beside where he knelt at his father's feet. He pulled on the gloves then waited until Castiel stopped pushing and met his eyes with a nod to lift the sheet. Already, he could see a small dark patch of hair beginning to emerge. Still watching it come, he spread a towel between Castiel's thighs just in case the birth got a little messy. As Castiel pushed again, the spot grew bigger, and Jack beamed up at him.
"I can see the first head," he announced with a grin in his father's direction though Castiel didn't see, eyes scrunched tightly shut with the effort of pushing. "Keep pushing; you can do this."
Several pushes later, the head was out far enough that Jack could cup it in one palm. As he did, he marveled at the feeling of it, and the realization that he was helping deliver his siblings struck him. He coached his father through delivering the head, calmly encouraging him to push through the burn when the head reached the widest part. When it popped free and Castiel fell back, gasping for breath, Jack grinned up at him.
"Almost done with the first one," he praised as he took a damp cloth to wipe up the baby's face.
Castiel whimpered and gave a few smaller pushes which helped the baby slip free into Jack's hands. The nephilim immediately snatched up the syringe and cleared its airways. As it began to cry and Jack placed it into Castiel's waiting arms, he noticed it was a girl before she was wrapped up in the blanket. He had a sister! Jack was so lost in awe at his new sister that it took him a second to remember to clamp and cut the cord – which, he remembered, was okay because he had to wait for it to stop pulsing. When he was done, he sat back and watched his father and sister with a small smile that almost felt a little forced.
Yeah, he'd been excited to have siblings that would be like him, but now one of them was here, and his father was smiling so lovingly at her, and Jack was just… there. He felt like an intruder, and if he didn't have his other sibling coming soon, he might have gathered up the supplies and left his father alone for a while.
"Jack," Castiel called, pulling the nephilim from his thoughts. "Would you like to hold her?"
Jack nodded eagerly, peeling off his gloves and gently accepting his sister into his arms. "Hi," he said quietly. "I'm Jack. I'm your big brother." The realization hit him and he grinned at Castiel. "I'm a big brother now."
Castiel smiled warmly at his children then tensed and his features tightened.
"Next one?" Jack asked, knowing the answer.
Castiel nodded, grunting as he pushed again, so Jack quickly yet carefully got up to place his sister in the bassinet that had been set up in the room for the twins. Thankfully, it only took a second to calm her slight fussing at being put down then he hurried back to the bed. He pulled out a second pair of gloves and took his place, waiting for the head. It only took a few pushes before another dark patch appeared though it disappeared when Castiel stopped pushing.
"This one has hair, too," he announced excitedly.
"Not surprised," Castiel grunted through a push. "Sam's got good hair..."
Jack chuckled at that. Attention back on his next sibling, he cupped the head in one hand as it slowly emerged. This time, Castiel expected the burn and powered through it though he was careful not to push too hard and risk tearing. When the head popped free, he fell back onto the pillows with an exhausted whimper.
"I can't," he moaned. "I can't do it anymore..."
"You're almost there, Castiel," Jack encouraged. "You've already delivered one. You can do it!"
"I'm tired, Jack," the seraph moaned.
"So finish this one then you can sleep. You told me you used to be a soldier, right? And you're the strongest person I know, angel or not. You can do this so push!"
Castiel stared in awe at his son then curled forward, grabbed the back of his thighs, and pushed as hard as he could with a determined cry. When the baby slid free, he fell back once more, chest heaving to catch his breath. Jack beamed brightly at him as he placed the second baby on his chest.
"This one's a boy," he said. "I have a sister and a brother!"
Castiel smiled tiredly as he cradled his newborn son, letting Jack gently wipe him down before he wrapped the blanket around him. "I'm proud of you, Jack," he said, meeting his eldest son's eyes when the nephilim's gaze snapped up to him in shock. "I mean it. You showed no fear and calmly supported me through this and you got to deliver your brother and sister. I'm proud of you," he repeated, cradling the baby in one arm as he reached the other out to tug Jack into his other side, pressing a kiss to his temple as he hugged him tightly.
Later, after Castiel had showered and the supplies had been cleaned up and the sheets changed, Castiel and Jack settled side by side in the bed with the newborn babies to rest. That was how Sam and Dean found them when they finally made it back to the bunker. After introductions were made and the awe of meeting the new babies had worn off, Castiel smiled with pride as he watched his eldest son recount the events of the birth. The pride and wonder in Jack's eyes lit up his face, and Castiel knew this would be what Jack would look like when he'd mastered his powers.