Author's Note: So this takes place sometime in Season 4, Selina is 18 and Bruce is 17.
Selina tiptoed into his room, the breeze lifting the sheer curtains around her. Clear skies allowed for the moon to shine brightly and illuminate his bedroom, letting her see him perfectly sleeping in his giant bed, the sheets pushed down to his feet not needed in the heat of the summer. She creeped in further, cupping her hands over her mouth to keep her giggles from escaping as she finds him completely passed out and snoring softly, wearing a thin white t-shirt and plain black boxer shorts, and lying spread eagle across the bed.
Selina on the other hand was not able to sleep that night, she had tossed and turned for hours not being able to find a comfortable position while sticking to her sheets and her pillow too warm. The bit of air that blew in from her open window every now and then felt like someone blowing hot air over her with a hair dryer. This heat wave was killing her. Finally fed up of staring up at her ceiling she slipped out her window and headed straight for Wayne Manor. Selina wanted to go swimming and the kid had a perfectly great swimming pool that he barely used. Unless you counted practicing to hold your breath while still fully dressed as using the pool.
Selina sunk her knees into his mattress, crawling over to him slowly, and leaned over him slightly as she started to poke him a few times in his shoulder only to have duck away as his arms swung out to swat at her.
"Jesus! It's me!" Selina hissed at him as he blinked up at her sleepily.
"Selina? What are you doing here? In my bed?!" Bruce asked in alarm, sleep vanishing quickly from his eyes as they widened by the second of her sitting there innocently.
"We're going swimming!" Selina announced with a small bounce of excitement, pulling his arm impatiently when he just sat there looking at her like she announced that she was going to join the circus. "Don't look at me like that, it's not an unreasonable request when Gotham feels like an oven!"
"And you had to wake me up for that at 2 in the morning? Couldn't you go swimming alone?" He said a bit irritated to have been woken up for one of Selina's spontaneous activities.
Selina rolled her eyes at him as she grabbed his hand and tried to drag him out of bed, "Everyone knows you shouldn't go swimming alone at night, what if I hit my head?"
"Okay okay, i'm coming, let me just grab my swim suit." Bruce said, giving in to her as usual. But Selina pulled at his hand again, directing them to his bedroom door.
"We won't need suits."
Bruce followed her out to the hall, his brows furrowed, "We won't?"
The two tiptoed through the house so as not to alert Alfred, slipping out the door towards the pool area. It was lit up prettily, Selina thought, with some of those fancy floating ballooned balls that had lights in them. Selina leaned down to flick her finger in the water to test the temperature. Perfect, being an in ground pool the water hadn't warmed up too much during the day, cool enough to still feel refreshed from the sticky heat. Bruce stood back and watched as she kicked off her shoes and pulled her socks off, and when she proceeded to pull her shirt over her head, throwing it on the ground, and then reached for the buttons on her jeans Bruce's pulse quickened. Selina turned around, clad only in a simple deep blue bra and matching panties, and gave him a devilish smile. Selina gestured to his own clothes, "Your turn, B."
Bruce gulped nervously but pulled his t-shirt off leaving him in only his boxer shorts. He knew he was being silly, her bra and panties were no different than if she wore a bikini, but they've never been this undressed in front of each other before. Even when they were sort of dating, they only managed to steal a kiss here and there, but then that dissolved almost as fast as it had begun. Their eyes connected and they both blushed, realizing they had been checking each other out.
Bruce cleared his throat, "So, time to swim?"
Selina grinned at him, walked to the edge of the pool by the deep end and held her hand out for his, "Let's jump in at the same time." Bruce took her outstretched hand, her soft palm sliding against his as he interlocked their fingers. On three they jumped, letting themselves sink to the bottom before pushing off the floor of the pool and breaking through the surface. Treading water they turned towards the Manor, holding their breath that Alfred or the ground security didn't hear the splash of the water. When the coast was clear they turned towards each other and laughed, Selina splashed water in his face and dunked back under, swimming towards the other end. When she came back up she had to duck before one of the lit up balloons hit her. Gaping over at the smirk on Bruce's face she smiled mischievously back at him, "Oh it's on!"
Selina and Bruce spent the next ten minutes in full war mode, throwing the balloons at each other, trying but not being very successful at being quiet, letting out whoops and soft shrieks in their game. It was a good thing Alfred's bedroom was on the other side of the Manor, Bruce thought, dodging to the left as Selina threw a blue balloon in his direction. Bruce revelled in their play fight. It had been so long since he could just be a teenage boy fooling around with his best the majority of the balloons ended up tossed out of the pool, leaving just one left floating closer towards Selina in the shallow end, they looked up at one another and then they both dove for the balloon. The slippery balloon slipped out of Selina's grasp as they both tried to grab a hold of it and they ended up slamming against each other. Selina laughed and started splashing water at him instead, Bruce doing the same. They could barely even see each other as they turned their heads away so as not to get any water in their eyes, but then Bruce reached out and grabbed her wrist pulling her towards him. Selina was still laughing and wiggling around to get away and Bruce didn't even think as he pushed her up against the side of the pool. They stood still looking at each other in a bit of shock at his forwardness, Bruce fully pressed against her, his hands still locked around her wrists, their chests heaving. Bruce slowly let his eyes drift down her face to her plump lips, and then further down her neck and chest, watching her bra covered breasts moving up and down with every breath. She looked absolutely stunning, her skin illuminated in the moonlight, drips of water running down the sides of her face and down her neck. He followed the trail of one down between her breasts.
"Bruce.." Selina whispered up at him ever so softly, entranced at the way he was looking at her. Like she was the only person in the universe. He dragged his eyes back up to her, half lidded and dark, and then she was shaking his hands off her wrists and reaching up to pull his head down to hers, their mouths colliding. Bruce kissed her back deeply, their lips melding together hotly while he let his hands slide down her back down to the small of her back. Selina wrapped an arm around his neck, the other around his back and pulled him impossibly closer, moaning as their hips pressed together. She could feel him through his thin boxers, how much he desired her and it made her feel lightheaded.
Selina had no intentions for this when she came here tonight. It seemed that no matter what happened between her and Bruce, something always drew them back to each other. They tried the dating thing, it hadn't worked out when he broke her trust. But right now, that felt like ages ago, and he had been slowly breaking down her walls ever since. Bruce felt like they'd been dancing around each other since they first met. He felt an unbreakable connection to her. And he knew now that she felt it too. He grunted as Selina wrapped a leg high around his hip and started lazily grinding against his erection. Her tongue was deep in his mouth mimicking her movements, and fuck- he did not think this was where they'd be when she woke him up to go swimming. She felt so good against him, better than any of his dreams. Selina pulled her lips from his and let her head fall back against the cement as she moaned and Bruce had never felt more turned on then in that moment.
Bruce threaded a hand in her curls, the ends soaked making her hair look longer. He pulled her head up so his forehead could rest against hers as he stilled her hips with his other hand. Selina blinked back at him, confused, "Bruce? Do you not want-?"
"Of course I do!" Bruce hurriedly assured her seeing the uncertainty in her eyes, "I just- are we really doing this?"
"I mean, I could go find another rich boy with a pool, if you change your mind." Selina said in a serious tone, but then she rolled her eyes at him, and he lets out the air he hadn't realized he had held in.
"Very funny, I'm being serious." Bruce said as he glared down at her. Selina stood on her tippy toes and kissed his lips lightly, pulling away just far enough to whisper to him, their lips almost touching, "I want this, Bruce. I want you."
Bruce barely let her finish before he captured her lips again, his kisses turned more frenzied. He felt her reach behind her and unclip her bra, and he helped her pull her straps down her arms. He was vaguely aware that she tossed it somewhere on the cement behind them but then his hands were cupping her breasts and all thoughts were gone except the feel of her soft flesh, her heart beating hard against his palm. From there they hurriedly stripped off their underwear, Bruce cupped her bare bottom and picked her up, her legs wrapping around his hips. He pressed her against the side of the pool, his head falling forward against her shoulder when she took him in her hand and guided him inside her. Bruce pushed forward, feeling her stretch around him, he wanted so badly to give in to his instincts, but let her have a moment when he heard her gasp and dig her nails into the back of his neck.
"Are you okay?" He whispered, worried that he hurt her. Selina nodded her head and opens her eyes with a small smile, "I'm good. Just go slow, okay?" Bruce started a slow rhythm, the both of them in complete bliss, but soon they were both panting against each other's lips, Selina moving her hips harder against his. They were so close, he could feel the tightening in his stomach, could feel Selina clenching around him and then she threw her head back and let out a beautiful moan, her body shivering in his arms. He took a moment to admire her, watched as she stilled with a soft smile and then he was letting go too, the pleasure so intense that he felt it down to his toes. While they were both still breathing hard, but savouring the afterglow, Bruce kissed her lips tenderly.
Afterward when they both pulled away, they shared a shy smile, holding hands as they walked out of the pool naked together. Bruce gathered up their soaked underwear and lead them back toward the Manor. Bruce took her upstairs to his bedroom after he tossed their wet clothing in the dryer, both of them giggling as they snuck around the dark, naked and dripping water all over the floor. Alfred will surely be puzzled in the morning, Selina thought with a cheeky smile, as Bruce pulled Selina under the covers of his bed, pulling her naked body against his. I wonder what Alfred will think when he finds their underwear in the dryer in the morning, She thought.
End Notes: Selina and Bruce just really needed to have some time alone together and de-stress lol