Jumping through dimensions was a usual thing for Sans when he was bored, which was a lot more now that his insomnia was getting worse. Ya know, from all the Genocide nightmares, yeah those. It never bothered him to the point where he'd want to leave his own dimension, especially after going in the Underfell universe by accident, but this felt like a good time to.

Zipping through 1s and 0s, he finally made it to a new dimension, it looked a lot like his own if it weren't for the tol skeleton in an orange hoodie and basketball shorts standing in front of him.

"YO." He said nonchalantly although he was practically shouting.

He looked just like his own Papyrus only more like himself, a lazy Papyrus? Well damn, seems like anything can happen in an AU.

"Sup?" Sans said, his signature grin plastered on his face.

"NEVER THOUGHT I'D SEE A LAZY SANS," he chuckled, "SO WHAT'RE YOU DOING HERE, LAZY BONES?"

"I couldn't sleep, you?"

"ABOUT THE SAME."

Papyrus motioned for him to follow, Sans was skeptical at first but thought nothing bad could really happen. It was Papyrus after all, even if he was from a different dimension, and if his Sans was still here (alive) then he shouldn't hurt him. . .right?

He led him into some part of the forest, the dark trees reaching higher than the eye sockets can see, the route was similar to the one Sans would use to hide from the world on one of his breaks. They stopped when they reached a large tree with a blanket near the trunk, yep it was definitely the place Sans would go.

"NYEHE, YOU LOOK SURPRISED."

Papyrus chuckled as he sat on the blanket, which was not covered by snow surprisingly, he patted beside him with a lazy smile. Sans shrugged and sat down beside him, sighing since he could rest and not be bothered by his own brother to get up again.

"SO HOW'S ME IN YOUR DIMENSION? YOU LOOKED SO RATTLED WHEN YOU SAW ME." He chuckled.

The puns were rolling off of him so casually that Sans didn't even realize it.

Sans shrugged, "he's. . .energetic and unique, so innocent the devil can change his ways for him," he chuckled, that last part hurt him a bit more than it should've.

"WOW, REALLY? ME ENERGETIC? AIN'T THAT A LAUGH," he chuckled, "YOUR PAPYRUS SOUNDS LIKE MY SANS, MY LIL BLUEBERRY ALWAYS BRINGS A SMILE TO YOUR FACE NO MATTER HOW DEPRESSED YOU ARE."

"Heh, seems like our roles have 'swapped' huh?"

"SEEMS SO."

They talked for a while longer, talking about the similarities and differences between their universes, until they started talking about their brothers again. By the time they got back to that particular topic though, their faces had turned flushed as some embarrassing things started to arise, especially one that had slipped just now.

"Hey, uh Swap Pap, have you ever uh," he coughed awkwardly, "oh I don't know-"

"WANTED TO KISS YOUR OWN BROTHER?"

Sans was shocked to say the least, he thought it was only him but it seemed not. He was even more surprised at the calmness in his voice (the blush was still there but he was still surprised).

"YEAH, THERE'RE TIMES LIKE THOSE BUT I COULD NEVER DO IT, Y'KNOW? SINCE WE'RE FAMILY AND ALL. . ." He slumped more against the tree until he was laying down fully on the blanket.

"Y-Yeah. . ."

A thought then came to Sans' skull, it was a long shot but maybe this could solve both their problems.

"Uh, Swapbro?" The taller skeleton hummed as he opened an eye socket, "this may seem crazy but. . .uh, how about. . .we kiss?"

Papyrus' sockets shot open as he stared at Sans who's skull was a deep blue, he wanted both of them to kiss??????

"I mean, if you want to. We're technically not kissing our own brothers since we're from different dimensi-!"

Papyrus grabbed his chin in his bony hand and brought his skull to his own, bonking their teeth together with a clacking sound, Sans was like a literal blueberry now and his sockets were like saucers. Papyrus pulled away slowly and looked into Sans' sockets, a bright orange surrounded his skull as he finally realized what he just did. He let go of Sans and backed away a little, sweating bullets as he panicked.

"D-DUDE, I'M SO SORRY, I DON'T KNOW WHAT CAME OVER ME!" He tried to explain, "I JUST. . .WITH YOU ASKING. . .I-I DON'T KN-"

Sans then stood up, his head was low and his fists clenched, Papyrus thought he was gonna freak since a blue mist was coming from the shorter skeleton's left eye. Sans stepped towards him and suddenly straddled him, Papyrus grunted in shock, his sockets still wide but in slight confusion. Sans started to unzip his hoodie, showing off his white T-shirt underneath.

"What're you apologizing for? We're just having fun." His grin grew.

Papyrus was on the corner of shocked and confused. . .but going straight to hell for what he was about to do.

Papyrus smirked as he watched Sans throw his hoodie off to the side, he sat up just enough so he rest back on the tree, he wanted a fuller view of what was bound to happen. Sans then started to take off his shirt, showing off his ribcage to the other skeleton, Papyrus then got the brilliant idea to stroke his ribs, which to a skeleton was one of the most sensitive areas of their anatomy. Sans froze with the shirt still covering his head, moaning through clenched teeth, Papyrus' smirk grew as he continued his actions.

Papyrus helped him pull off his shirt and immediately dove into his neck, conjuring an orange ectotongue to lick the base of his neck and grazing his phalanges over delicate ribs. Sans shivered at the contact, he placed his hands on his arms to stabilize himself, he moaned through clenched teeth as Papyrus' tongue dipped into the space between his neck bones and clavicle. Papyrus moved his hand ever so slowly down the smol skeleton's frame until he met the waistband of his pants, slipping a finger in and grazing his hip bone.

Sans bucked into him unconsciously and Papyrus grunted slightly, Papyrus groaned and licked his neck more furiously, biting his clavicle every now and then. Sans wrapped his arms around the other's neck, pulling him more onto him, Papyrus smirked more and moved his head lower, grazing his tongue along Sans' sternum.

Sans grinded against his groin, earning another grunt from the tall skeleton, and a scoff from his own lips- teeth. Papyrus growled as he pushed Sans on the blanket so he was on top, Sans shrieked a little and his sockets grew wide in shock, the smile on Papyrus' skull only made them grow.

"SO YOU WANNA PLAY GAMES HUH? OKAY, I'LL PLAY ALONG." A malicious smile played on his teeth.

That sent another shiver up his spine, not from fright but by excitement maybe?

Papyrus yanked off his pants and roughly rubbed Sans where his pelvis and sacrum were connected, Sans jolted under him and let out a gasp, his back arched off the blanket and his mouth opened slightly, Papyrus pressed his teeth against the other again, Sans formed his own tongue and played with Papyrus'. The two wrestling for dominance that the bigger skeleton soon won.

His coccyx wagged happily behind him, making a soft fluttering sound against the blanket. Papyrus hummed and pulled away from him with a raised eye ridge, Sans was panting under him and groaned impatiently.

"W-why'd you s-stop?" He panted.

Papyrus looked down and saw his tail, "WOAH, YOUR TAIL IS TOO ADORABLE." He smirked.

Sans gasped when Papyrus took ahold of it, stroking the bone experimentally and earning a shivered moan from the smaller skeleton, a blue light emanated from between them. Papyrus looked down again and saw a bright blue ectocock between his legs, Sans was too dazed to notice and his eyes were closed. Papyrus bent down more and licked the glowing appendage. Sans screamed in pleasure, his member jerked against Papyrus' teeth and the taller skeleton smiled more.

Papyrus stuck his whole member in his mouth, Sans was big but Papyrus' jaw was larger. He sucked on his member at a moderate pace, bobbing his head up and down while stroking his tail more, Sans moaned and he placed his hands on top his skull, pushing him down lower on his ectocock. Papyrus hummed too himself, sending a jolt to Sans' member and making him stiffen, before he knew it a creamy substance splurted into his mouth.

Sans came.

Papyrus went down one more time and made sure he got all of his blue before letting go of his member, Sans' eyes were void for a couple of seconds before the little white pinpricks came back, he panted and blushed a deeper blue when Papyrus showed him what he had done before swallowing and smirking.

"NYEHE, LOOKS LIKE I BLUE YOU AWAY, HUH?" He snickered, Sans could only blush more with wide eyes.

Papyrus then pulled down his shorts, revealing his large and orange ectocock, the only difference between them was the length, he placed Sans' legs around his waist and hovered over him.

"MIND CONJURING A HOLE SO WE CAN CONTINUE?" He asked softly.

Sans shook his head anxiously and he conjured a backdoor for him to enter, Papyrus brought his hand to Sans teeth, "SUCK," he demanded. Sans shivered and happily complied, grabbing his wrist and licking on his fingers fervently. Papyrus liked the sight before him, a panting and obviously aroused Sans licking on his phalanges like his own personal pet, even if it wasn't his brother it was still a brother of his. His little blueberry.

After a while he pulled his hand away and brought it to his hole, slipping his middle finger inside, Sans shuddered and moaned against him, his grip on his arms tightening as he added another finger. Stretching and pumping, scissoring him until he was ready. Papyrus removed his fingers slowly, straightening his back as Sans whined from the lack of contact.

He then positioned himself at his door, Sans gave him the 'ok' and he plunged into uncharted waters. Sans moaned loud at the sudden intrusion but he liked it. A lot. Papyrus thrusted into him at a moderate pace, stroking his ribs and kneading his pelvis, one of Sans' hands was above his head while he bit on a finger of the other hand, trying to keep quiet so no one could hear him. Condensation started to drip from their bodies and onto the blanket, Sans' head started to feel light, his vision blurring and a pressure starting to build in his nonexistent gut.

Papyrus could feel his insides twitch around him, signalling he was close, he was too, Sans was so tight around him that he's surprised he lasted this long. Papyrus' left socket glowed a neon orange, Sans felt something slender wrap around his dick, when he looked down he realized it was a large orange tentacle and more sprouted from behind Papyrus as he had a malicious grin on his face. The tentacles nuzzled and nudged different parts of Sans' body, making him shudder and buck under him, the tentacles were slick with some yellowish substance coming off of them, making him feel sticky but he didn't mind. It wasn't until he felt the tentacles massage the inside of his ribs, his arms and legs and his *ahem* bone that he screamed out in pleasure. Blue goo squirting out of his member and onto his bones, Papyrus came soon after him with a shuddering grunt as his walls tightened around him, his orange goo adding to the blue palette on his body.

They both huffed as their bodies attempted to calm down, Papyrus stared at the sight before him. Sans covered in both their cum, panting and sweating hard, and still twitching from his orgasm and the touches of his tentacles that nuzzled him. Sans watched as both their members and the tentacles dissipated into nothingness, sighing when he felt the skeleton's mouth on his neck again.

"Well damn. . . Swap Pap. . .you sure rattled my bones there." He chuckled tiredly.

"DAMN STRAIGHT I DID, GOOD TO SEE I DIDN'T MESS UP YOUR FUNNY BONE THOUGH." He snickered.

They stayed like that for a while before they cleaned themselves up and put their clothes back on, but they returned to their laying positions, Sans was laying down on Papyrus' chest and both hugging each other tight.

"CAN I HOPE TO SEE YOU AGAIN?"

"Sure, I wouldn't mind coming back." Sans yawned.

They soon fell asleep after, not knowing a figure was watching them from a distance the whole time, grinning to themselves maliciously as they walked away.