AN: This was inspired by nsfwparadise8's prompt on tumblr that had been reblogged by and is dedicated to thatsrickdiculious because they wanted to read this so badly. I hope I was able to please with this even if it's super short.
I'm also looking forward to your take on this (if you still want to write one, too).

Warnings: Rick/Morty, omorashi (aka pee kink), masturbation

Nightly Accident

Morty waved after the departing station wagon as it drove down the street. His family had decided to have a camping trip this weekend, but Rick had declined coming along, claiming that he had a very important science project to work on and also stating that Morty had to stay to help him with it.
However, this had been a complete lie. The truth was that the two just wanted to use this rare opportunity to spend the weekend together alone and undisturbed by the rest of the family.

It had been only a few weeks ago that the two had stopped tiptoeing around each other and Morty had finally confessed his feelings to Rick. After another week of awkwardly avoiding each other, Rick had finally returned his feelings and so they were together now…albeit secretly of course.

Untypical as it was for Rick, the scientist had decided to take things slow with Morty because the boy was special to him. Always had been.
That's also why he hadn't just bent him over his workbench and took him right then and there – something that he would have done without a doubt if it had been anyone else. In fact, they barely had participated in any activities that could be considered intimate yet.
Rick had taken him out on some dates off planet, just eating out or going to the movies and they had been holding hands and even making out a few times, but aside from that, nothing else had happened between them yet.
Morty didn't mind though, actually finding it sweet of his grandpa to let this relationship develop at its own pace.

So, the simple plan for tonight was just some movie watching while cuddling on the couch. Rick had gotten the movie, snacks and drinks while Morty got pillows and blankets so they would have it comfy.
It was actually nice to be able to snuggle together like this, without having to worry that someone from the family could walk in any moment and they quickly would have to separate and act as if they hadn't just been doing something that was exceeding the limit of a normal grandson-grandfather-relationship.

Morty quickly got into the movie that Rick had picked because it was really great and had a bit of everything. Hilarious scenes that made them both laugh their heads off. Amazing action where neither dared to blink in order to not miss even a second of it. Suspense that had Morty at the edge of his seat – albeit in a more figurative than literal sense. And even some romance that made the boy blush and lean a little closer to Rick, who put his arm over his shoulder in return.
However, that last scene turned quickly very erotic and Morty's head as red as a tomato as he squirmed a little in his seat, suddenly feeling a bit too warm. Thankfully, Rick hadn't commented on that, even though he surely must have noticed it.

Still, it was undecidedly the best movie that he had ever seen even though it was double the length of what was considered standard in their dimension.
Through it all, Morty had been steadily devouring the snacks that had been laid out on the couch table in front of them. Since the chips were especially spicy, he was forced to fight the dryness in his throat with something and had been hugging an XXL bottle of soda to his side the entire time. Funnily, he barely even noticed that he had drunk all of it.
By the end of the movie, he had abandoned the empty bottle and had already finished half of another one. Well, thankfully his thirst was gone now.

"Well, kiddo. Guess we should call it a night, or what do you think?" Rick got up from the couch to stretch his arms just as the credits began to roll across the screen.

"Um…well…I thought…m-maybe we…" the brunet fiddled with the hem of his shirt as he tried to bring up another idea that he had in mind since it was clear that they would have the weekend to themselves.

Surprisingly, Rick waited patiently for him to say what he wanted and this gave Morty finally the courage that he needed. "I was wondering i-if we could sleep together?"

As his grandfather lifted one side of his single eyebrow, he hastily continued. "I-I-I mean, really just sleeping! Like in one bed! Only sleeping! Nothing else…"

Morty's face felt so hot that he knew he was blushing, but the tension began to drain from his body as Rick chuckled and ruffled through his hair.

"Sure. Change into you PJ's or whatever and come to my room. Okay?"

The boy's face lit up like a Christmas tree and he hurried upstairs to change. After switching his regular t-shirt and pants for his yellow pajamas in record time, he quickly went to the bathroom to brush his teeth.

Gosh, he was so excited! This would be the first time that they would actually been sharing a bed.
Sure, over the course of their adventures, they had been occasionally sleeping together in one small space, but they never really slept together together. When they stayed at an alien motel that had only one room with one bed, then one of them usually slept on the couch, chair or floor. And even when they only had Rick's space car, his grandfather always let him sleep in the backseats while he lowered the driver's seat and slept on there.

As Morty hastily did the last brush strokes, he kept reminding himself to use the toilet real quick, too. He was surely going to need it after all the soda that he had drank.

"Morty, hurry up or I won't let you in my bed!" Rick's sudden shout from downstairs made the boy panic and spit out the foamy toothpaste in his mouth.

"I'm coming already, Rick! I'm on my way!" He shouted as he dashed out of the bathroom and back downstairs to the spare guest room in which his grandpa resided in since he had moved in with them.

Unfortunately, in his haste he had completely forgotten his plan to use the toilet.

As he entered Rick's room, the man was already waiting for him in only a white tank top and boxer shorts. He motioned Morty to get on the cot so he would be sleeping next to the wall before moving in after him.

The boy's heart was fluttering nervously, as his grandfather turned off the small lamp on his bedside table – the only source of light in the room – and then wrapped his arms around him.
Of course, he knew that they were only going to sleep innocently and yet his heart was racing and his face heated up again at their closeness.

God, he felt so nervous that he wasn't sure if he could even sleep tonight.

Yet, encased in the warmth, smell and strong arms of his lover, Morty fell asleep surprisingly quickly.

His sleep didn't last for long though.
He moaned groggily as he opened his blurry eyes a little bit and had to orient himself. After noticing that he was sleeping in Rick's bed, the next thing that he wondered about was why he had suddenly woken up. It was still dark and obviously in the middle of the night and if Morty had to guess, he had probably slept no more than one or two hours.

A pressure in his bladder pointed out to him not even a full second later why he was awake now. Also, it was only now that he suddenly remembered that he had wanted to use the toilet before going to bed and had completely skipped it because Rick was hurrying him.
That had been really stupid of him and he should have just told Rick to wait a little moment longer while he was finishing his business first. Well, now it was too late and couldn't be helped anymore.

Morty was wondering if he could actually get up without waking Rick, but seeing how small the cot was and that he would need to climb over his grandfather, too, it was very unlikely that he would make it. Aside from that, Rick still had his arms wrapped around him.
Still, feeling the incessant pressure drove the brunet to give it a try.

He tried to carefully entangle Rick's arms from around his body, but the man didn't budge even a single bit. Next, he tried to wriggle his way out and underneath them, but that also wasn't crowned with success as his grandpa held on a little too tightly to him.
In one last-ditch attempt, he tried to use a little more force and pushed against the lanky arms, but unfortunately that resulted in Rick suddenly hugging him even tighter, which made Morty squeak quietly as more pressure was added to his already full bladder. The man hadn't woken up, but he mumbled something that sounded like Morty's name in his sleep and nuzzled the boy before snoring again.

The brunet knew that the only thing he could do now was to wake Rick up, but he was just so cute and cuddly now – something, which was incredibly rare coming from the old man – that he didn't have the heart to do it.
Maybe if he just ignored it, he would be able to last until morning? Yeah, maybe if he manage to fall quickly back asleep, he wouldn't even notice and wouldn't need to go until he woke up again!

So, Morty clenched his eyes shut and tried to ignore his bladder that was screaming for release, focusing solely on falling back asleep again.
Needless to say that this didn't work and after several more minutes the pressure had grown to unbearable levels.

There was no way around it. He would need to wake Rick up and explain to him that he needed to use the bathroom even if it might make the old man all grumpy from interrupting his sleep.

"Rick?" He whispered tentatively. "Rick? Please wake up, Rick!"

Not getting a reaction, he began to shake his grandpa slightly. This time Rick did react to it, but unfortunately only by tightening his hug once more, which made Morty whine since it did not only start to become slightly painful, but also because it was adding more uncomfortable pressure to his overfilled bladder.

"Oh god, Rick! Please wake up! I really need to go!" He said now louder.

Morty wasn't even sure if he would make it to the toilet in time even if Rick did wake up and let him out of bed now.
Shaking tirelessly, coupled with the far louder whispers, finally made his grandpa let go of him and turn on his back. However, this just wasn't Morty's night because in the same moment as he sat up, Rick moved once more and elbowed him straight in his over sensitized bladder.

This in turn caused the boy to lose control of his pubococcygeus muscle and he jolted in surprise with a loud gasp while a slow stream of pee leaked out and quickly soaked his underwear and pajama pants.

Morty's noises and movements finally caused Rick to wake up. "Morty? Wha—?"

He abruptly stopped asking his grandson what was wrong as he felt a slightly warm wetness dampening his boxer shorts. With wide eyes, he stared in the semi darkness at the crying and blubbering mess that was Morty.

"Oh god, Rick! I'm so sorry! I-I didn't mean to! I ju-just needed to go so badly and you didn't wake up! Oh god!" He was so embarrassed right now, that he couldn't even look his grandfather in the face.

Rick was silent for a moment more before he fully sat up.

"C'mon, let's get you out of these." With that, he made Morty lay down on his back so he could pull both of his soiled pants and undergarments down in one motion.

While Morty felt a little embarrassed that his lower body was now bare, – though this wasn't the first time that his grandfather had seen him naked – he was also grateful because the soaked clothes had been quickly starting to cool down and felt uncomfortable. Also, Rick didn't sound angry, so that was a good sign, right?

"I-I'm going to clean up and then I, uh, help you change the sheets, Rick." He said awkwardly and was about to sit up.

However, Rick pushed him down again. "Huh?"

"Not so-not so fast, Morty." The elder massaged Morty's lower body with his right hand, making the boy squirm.

Even if he had accidentally urinated a little bit, the brunet's bladder was still full and sensitive. He really needed to use the bathroom and relieve himself.

Of course, Rick had noticed how much soda the boy had been guzzling down tonight and knew that he had more to give than just that.

"Stop, Rick! Please, stop! I-I have to use the toilet. If you-you don't stop that, I will-I will…" he begged, not understanding why the other was doing this and trying to push Rick's hand away.

However, Rick's arm was unmoving – unrelenting – and he became once more aware of how much stronger his grandfather was than him.

"Eh, eh, eh, Morty. Bad-na-naughty boys who wet the bed need to get punished." The elder chastised him and added more pressure to Morty's abdomen.

The boy whined and tears were welling up in his eyes again. "No, Rick. Please. I di-didn't mean to."

He clenched his eyes shut as he focused all his will power on keeping it in and his body began to painfully cramp up.

"Please, Rick. Let me go. It hurts…"

His grandfather made some shushing noises. "Just let it out, Morty. C'mon. You're only gonna hurt yourself like this. It-it isn't healthy."

Morty couldn't believe that Rick really wanted him to do that right here.

"Relax and let it go, Morty." Rick breathed into his ear.

Seeing no chance to escape from this since the other was holding him down and massaging his swollen bladder with one hand, Morty finally caved with one last wail of mortification. At first, only a few small golden drops escaped, but the slow trickle quickly turned into a steady stream.
Despite the grossness of the situation, Morty noticed that in a weird way the wet warmth actually felt nice on his skin.

A drawn out moan of relief slipped past his lips as the tension finally drained out of his body. It was echoed by a groan that made him dare open his eyes again.
Wandering down the length of his grandpa's body, he could see that Rick had pulled down his ruined boxer briefs and was furiously fisting his hard length.

Another wave of heat flooded Morty's body at the sight. For one because, damn was he big!
Also, he couldn't believe that Rick was actually getting off on this. Although, he couldn't deny that he was slowly becoming aroused himself.
Unable to stop now that he had started to empty his bladder, he could feel the warmth spreading all over his lower body, legs and underneath him, too, reaching his buttocks and lower back.

Eventually, the yellow flood stopped again, finishing with the last few, slightly painful drops. Yet, Morty didn't move, continuing to lay in his own piss and watching Rick.
His grandpa sat up further and still ruthlessly pumped his erection while staring down at the filthy mess that was his grandson. Aiming for Morty's abdomen, he added to the filthiness by squirting his cum all over him, his jizz being like the icing on top of it all.

Unfortunately, this didn't help the brunet's stiff and twitching arousal that had formed in record time and was hard to overlook now.
Another gasp escaped Morty as Rick was taking aim anew and suddenly peeing on him. He could feel it soak through his pajama top, running over his chest and pooling in the flat of his stomach as his grandfather worked his way slowly down. Morty moaned loudly when Rick reached his lower body, feeling the renewed heat on his quickly cooling body and he couldn't help but reach down and touch his own cock now.

It only took him a few pumps before he came with a weak cry, his cum intermingling with the last drizzle that Rick wrung from his spent dick.
His chest heaved and his body trembled in a mix of aftershocks and quickly seeping in cold thanks to the drenched clothes and liquid that still clung to his skin.

So much for taking thinks slow in their relationship. Well, Rick Sanchez had never been a very patient man to begin with, so this should come as no surprise.

"C'mon. Let's go shower and after that clean this mess up." Rick said as he peeled the drenched pajama top from Morty's shivering body.

After giving his cot a quick once over, he quickly thought over his decision again. "On second thought, let's crash in your bed tonight."

AN: I have to admit that this isn't my best work and it feels sloppy and rushed (even though I took my time with it), but I hope that you still enjoyed it. I might try to write a better one for this kink in the future though.