It was looking to be a fun day in the Underground for Asriel! He was ready to swim with his friends and play with no school to worry about. Even down in the darkness it was a rather hot summer.
     “Asriel, dear, are you getting ready?” A friendly goat mother’s voice asked from behind his bedroom door.
     Little Asriel mumbled as he started taking off his pajamas and changing into his swim trunks. He tugged down his bottoms and had his shirt pulled over his head when his mother opened the door.
     “You did not answer, are you alright, dear?” Toriel checked in on the little guy mid-change.
     “Mom!!” Asriel gasped - his little white butt facing her with a scared waggle of his tail. Realizing his butt was exposed to her, he covered it up with his fluffy tail.
     “Oh dear, I am sorry.” Toriel apologized with a smile, “I did not mean to see your little tushie.”
     Asriel blushed, his shirt still covering his face as he turned around. “Please get out!”
     Toriel closed the door after giving a little motherly giggle from what he’d just exposed.
     “Gosh...” Asriel blushed, taking his shirt off before finding his green swim trunks and a little white tank top. He put on a pair of sandals and headed out of his room.
     “You already leaving, champ?” His father opened his bedroom door enough for his face to pop out. “Your mother and I will join you there shortly. I seem to have misplaced my trunks...” The young goat’s father turned around, showing his much larger, chubby white buns as he went back to searching for his clothes. 
     “I’ll help you, dear.” Toriel giggled as she walked by Asriel, “Always losing everything...”
     Asriel opened the door to head out before his parents interrupted yet again - he couldn’t do anything without them babying him.
     “Make sure you go potty before you go swimming dear.” Toriel reminded him.
     “Yes, you’re a prince! Make sure to be on your best behavior.” Asgore chuckled.
     Asriel nodded and ran out the door.

     The Underground was full of puzzles, or at least, that’s what it was known for. By now, Asriel knew which colored blocks to step on during his trip to the city. They eventually got trickier, he hadn’t been down to the pools since last summer and forgot some of the puzzles.
     “Step on the hole with the same number of bells in the east tower...” Asriel read the sign, “Which whole is for which number?” He kind of had to guess - so he put his sandal-wearing foot over one of the middle holes. He heard a buzzing noise - wrong! A big gust of wind blew upwards, making his shirt fly right off his skinny body.
     “Hey!!” Asriel gasped innocently, covering his chest as he had to pick it off of a nearby gate. He held his shirt tight and stepped over another hole. Wrong again - an even stronger gust of wind flipped him on his back, and blew his swim trunks right off his butt!
     “EEP!” The little goaty blushed, seeing his bare naked legs above his body, with his trunks up in the air. He looked lower and whimpered, seeing his own special parts out in the darkness of the day! He’d never lost his shorts in one of these puzzles before. He crawled up to get them, but they blew over the gate he needed to pass!
     “Oh gosh, I’ve gotta hurry through this one before anybody sees me. I’m a prince!” Asriel closed his eyes and stomped his hoof down over one of the holes. Like the others, it blew up air right between Asriel’s legs! But without shorts on, he just felt a lot of funny wind against his little goat parts, and right against his furry butt cheeks. It tickled! He couldn’t help but laugh, but he did his best to push his shirt down to hide his privates from anyone nearby - seeing them jiggle and dance about in the wind was a very intimate thing, and he knew his parents would be upset if others saw.
     Either way - This was correct! He heard a little jingle from the gate as the doors opened, and Asriel was free to pass. The shy goat boy looked both ways before lowering his shirt and running through it bottomless. His tiny butt jiggled with every step as he found his shorts on the other side and bent down to pick them up.
     “Nice Assriel!” A raspy young voice laughed behind the prince. Asriel picked up his shorts and covered between his legs with them as he turned around. It was Monster Kid! ...Who well, he’s just a much much younger kid than he might be later on... but still kid enough. Anyway.
     “Hey...” the little goat blushed.
     “Don’t mind me, prince! Are you gonna go swimming too?” Monster Kid asked, also wearing some swim trunks.
     “Yeah! I’m having trouble going through all the puzzles. Can I just follow you?” Asriel almost begged.
     “Sorry, I just got back from there! Turns out, I’m not a very good swimmer. Maybe next year.” The little one shrugged before he turned around towards a bush. Asriel looked a little confused, and was honestly waiting for him to look away so he could get dressed. However, he watched Monster Kid use his foot to lower his shorts and show off his little scaly butt before the sound of faint tinkling could be heard. He was peeing in the bush out in public!?
     “Sorry yo! When you gotta go, you gotta go.” Monster Kid laughed after he aimed a bit with his hips. Asriel blushed and looked the other way. It reminded him he might need to pee eventually too!
     Asriel looked up ahead, and two girls were in plain sight - they were older than the two of them, but here he was almost naked, and here was Monster Kid peeing almost within their range! Wasn’t he embarrassed? Wouldn’t he worry about them noticing and getting a look at his penis? Or think he’s weird for peeing outside? They didn’t seem to be coming near, so Asriel was thankful for that...
     When Monster Kid finished up, he just stood nervously for a moment. “Uh, hey Asriel, can you help lift my trunks back up? I’ll turn away and let you put your pants on privately if you do!”
     Asriel rolled his eyes - a prince wasn’t supposed to be someone’s servant, right? Then again, a good prince was probably supposed to help the people... so he looked away and walked up, grabbing his trunks with a free hand and pulling up once over each leg.
     “Hey thanks!” Monster kid giggled as he ran off in the other direction.
     “Phew...” Asriel sighed. He wiggled his cute little tail above his white butt - reminding him he was still bottomless! He bent down to put his trunks on when a hand from behind spanked his bottom playfully.
     “Hey Asgore Junior,” a chubby yellow reptile walked by. It was Alphys!
     “Ah!! H-Hey...” Asriel blushed, quickly pulling his trunks up and standing up straight.
     “Why’re your pants down?” she laughed, before seeing the wet bush in front of Asriel. “...Wait a minute, did you just pee out here?”
     “No!!” Asriel whined, turning around, “Someone else did. It wasn’t me!”
     Alphys’ face turned bright red. She looked down at Asriel’s swimsuit, and there was a white bump sticking out of the very top...
     “Uh...” All she could do was point at it.
     Asriel looked down at his shorts, wondering what the big deal was. He quickly found out what it was! Not the biggest deal, but the tip of his little one was sticking out above the waistband of his swimming trunks. He yelped and quickly pulled his trunks up more - it must have gotten caught when he rushed to put them on!
     Asriel thought to himself, “I can’t believe she saw my... my...” his face scrunched up shyly, he wasn’t supposed to let anyone see his private little body!
     “Ohh, it’s okay. Asgore has one of those too. All boys do! I’m a scientist, it’s no big deal...” Alphys pat on top of his head and went along her way, hoping Asriel wouldn’t get much more upset.

     A few more gates were on the way to the pool. Asriel had to try and do a secret high five with a mechanical pair of arms - however, it ended up squeezing his little butt, and his parts right between his legs! The arm even tickled his tummy, which made him feel like he had to go potty. He started to squirm as he made his way through.
     “Alright... one more test before I can swim!” Asriel clapped his hands. The final gate had a large tube full of water connected to it. Inside the tube was a key, and outside the tube was a label that simply said, ‘drink’.
     It seemed like a lot to drink up, but it was a simple task. Asriel felt like a pet in a hamster cage as he bent down and drank from the bottom of the tube, filling up with water, quite wide and cartoonishly. It might not be tht easy with so much to drink, but it was simple! 
     Asriel felt his tummy grow, his hips and arms and legs all grew wide - maybe this was more than just water? He just had to drink a little bit longer...
     RRRRRRIP!!
     ...Asriel’s swimsuit ripped in half!
     The big chubby goat looked back at his fat naked butt as his green trunks ripped off and fell down, totally exposing his underside! His tank top shortly followed, leaving him completely nude. Asriel panicked, taking his mouth off the tube, he squirted out all the water from his mouth to go back to his normal size. He was happy to be his skinny goat self again - but that didn’t fix his swimsuit problem! He was naked out in the Underground!
     Asriel didn’t bother getting the scraps of clothing for cover - he ran right into the gate, covering his front and behind as he moved ahead.
     On top of being naked, Asriel felt a new problem. He really had to pee! This was almost too much for the little goat-esque monster. He looked around, maybe there was a restroom he could use at the pool - it would be helpful, but there wasn’t any! A lot of monsters in the underground seemed to insist they didn’t use the bathroom. Maybe that was true for skeletons, but Asriel sure needed to use one!
      The pool was right there though, he could just jump in and pee, nobody would notice! His parents told him not to, and he knew he shouldn’t, but other monsters were in the area and he didn’t want to be seen. One quick dash would be just perfect if he could make it. But just as he started to run for the pool, he felt a big hand on his shoulder.
     “Howdy, Asriel.” It was his father!
     “Hello dear, you finally made it.” Toriel put her hand on his other shoulder.
     “Mom? Dad?” Asriel blushed, covering himself.
     “We’ve been waiting for you, why did you take the long way around?” Asgore chuckled, “Where’s your suit?”
     “And your shirt. Where did your shirt go?” Toriel looked down at the little guy.
     Asriel blushed, eyeing the ground. He started shaking his hips and doing the potty dance. He couldn’t just stay in place. Being naked right between them and out in public made him so tense and nervous. His parents just wouldn’t stop talking and kept asking questions... it was like he was trapped!
     “C-Can we talk later? I gotta go home and get a new suit!” He tried to make an excuse.
     “But you were just running towards the pool...” Asgore chuckled.
     “You weren’t planning on skinny dipping, were you?” Toriel asked, overloading him with questions.
     “Stooooop! I have to...” Asriel bit his lip and raised his leg, pushing his pelvis into his paw to try to keep his pee contained. He tried to look for a way to get away from them, away from everyone and hide, but he was surrounded and felt something wet in his paws...
     “Oh no!” Asriel thought as he looked down, seeing a small stream of yellow liquid squirt out of his hands. He tried to push down more to stop it or hide it, but it was too late! Asriel submitted... holding himself for a minute as he peed in public, all the monsters, including his parents, watching a puddle form under his legs.The little goat looked down and closed his eyes, not really wanting to get his hands all wet (pee was strangely hot and warm! He’d never really noticed...) he removed his hands from his winky.
     The pool gasped as they saw his tiny little monster wiener, white and fluffy, simple hanging out rather short on top of his tight, nervous balls. They could see the yellow stream coming right from his weenie. Some of the monsters who didn’t have theat kind of body part watched, fascinated seeing it for the first time. Boys blushed at the sight of another guy showing off what they looked like to everyone. Girls giggled, getting to see something new and naughty they weren’t supposed to see out in public...
     Asgore and Toriel looked at each other, not sure what to do! Asriel’s cheeks were red - he only had to pee a little bit but that final puzzles really filled him up. Eventually his stream stopped, pitter-pattery noises of his pee hitting the ground coming to an end. Toriel and Asgore finally put their hands in front of their son’s little privates as he stood there, still embarrassed, no idea how he’d live this down.
     “Oh, don’t worry dear, let’s have your father wash you off...” Toriel lead the two off to one of the little showers out by the side of the pool. “I will go fetch you a cute little swimsuit for you to wear. Perhaps we should try a speedo this time, so it does not fall off so easily...”
     “Mooooom!” Asriel whined, as he headed to the showers, huffing at the sight of his fur colored in an embarrassing yellow color. He’d soon be hearing others call him by his new nickname, ‘Asriel Pee-murr’.