It was 10:57 at night. The white snow was now illuminated by the moonlight that shone all around Snowdin. Sans's steps made a soft crushing sound as he walked on the snow on his way to Grillby's bar. Once he pushed one of the double doors open, he was immediately greeted by the warm atmosphere caused by Grillby, the fire monster.

Sans looked around to see if any of the few remaining costumers were familiar to him as he made his way to his favorite spot at the bar but there wasn't anybody he recognized. He noticed Grillby was standing by the door escorting two costumers out and giving a friendly "thanks for coming" quote. Only two costumers were left now and they were in the middle of their dinner.

"You picked a lousy time to show up, Sans. Why am I not surprised?" Grillby's soft whisper-like voice increased in volume as he made his way to the bar.

Sans looked at the time. It was already the first few seconds of 10:59.
"Well, why would I go a day knowing you didn't get to see your favorite costumer?" Sans said with a chuckle.
Grillby just exhaled a puff of air, "the usual?"

"Would it be unusual if I would get another thing besides the usual?" He winked when he mentioned the punchline.

Grillby just stared at Sans for four seconds then left to get a bottle of ketchup.

"That's one big bottle, I guess I have a new bottle to ketchup on." Sans winked at the last word.

Grillby couldn't help but chuckle this time.

"Ok, now that was funny, I'll give you that." Grillby said at last.

"No autographs, please." Sans joked before he took the ketchup and began to drink it.

"See ya later, Grillby, thank you so much for your service." one of the pair of costumers said as they both walked out the door at the same time.
"Have a nice evening." Grillby said. He walked to the used table and began to clean it up. After the table was cleaned, Grillby brought the used dishes to the kitchen. He looked at the time, the clock showed it was already two minutes after closing. He decided to wash the remaining dishes tomorrow and check if Sans was still there.

Sans was obviously still there with the ketchup bottle now empty and him now asleep. Grillby sighed.

"Typical Sans." Grillby said and began to wake Sans by shaking his shoulder, "Closing time, Sans."

"What! What!" Sans jerked up. He relaxed once he saw Grillby, "oh yeah, closing time. Just put it on my tab, Grillbz."

He got off the stool and began to make his way to the double doors. After two pulls, he realized it was locked.

"You are not going anywhere," Grillby said with an irritated voice and pulled Sans back by his hood.

"Grillbz, what's gotten into you?" Sans says naturally. That annoyed Grillby even further. He roughly pushes Sans back to the bar until his back touches the table. He leans his angry face near Sans to make eye contact.

"Pay your fucking tab for once or I will make you pay for real."

"Come on, Grillby. You know I will pay it either way... Eventually." Sans responded a little intimidated by Grillby's glowing fire yet still kept his voice calm.

"Then do it now, or I swear to Asgore I will-"

"Or you will what, Grillby?" Sans interrupted with a challenging voice.
After another stare, Grillby's face showed a hint of a mischevious smile.
"Or I will leave you limping for days." He responded back to Sans before he took hold of Sans' arms and tossed him on one of the many tables located at the center of the bar. Sans' back landed on the surface of the nearest table.

The skeleton monster had no time to sit himself back up before Grillby closed his chances of escape by placing his hands on Sans' upper arms.

"It will be one way or the other. You decide." Grillby said firmly as he made Sans feel his growing cock on the upper inside of his shorts by slowly grinding on him. Sans was no longer calm. He was now surprised at how fast Grillby has gotten hard and how he was now feeling the blue magic in his shorts become hard too.
Grillby noticed Sans' excitement and began to grope it through his shorts. Sans' moan was long and his face began to blush a deep shade of blue and boy did it look so sexy.

"Well?" Grillby's eyes focused on him when he felt Sans' hips rise against his hand, "what do you choose?"

"Grillby..." Sans moaned again drooling blue saliva at the same time, "make me pay for it."

Sans' laugh was interrupted with a groan when Grillby's grip increased suddendly.

"Every last piece." Grillby said as he quickly removed his own shirt revealing his toned torso.

"So hot." Sans commented and immediately sat up to unzip Grillby's fly. He wanted to only focus on Grillby's face and nothing else but kept his shirt off as his upper body was now part of his favorite things.
Grillby placed his right hand on the back of Sans' head and watched as Sans willingly took his hot rod out and immediately leaned in to lick and suck it.

Grillby's breaths were beginning to increase as Sans gave him pleasure. He tried to fit more into Sans' mouth by pushing his right hand until he felt his tip rub against Sans' throat.

Sans's gag reflex reacted instinctively but he knew Grillby was enjoying the feeling based on how his breath hitched right away. Sans smiled around Grillby's dick and lifted his bony hand to pump the part he couldn't fit in his mouth as hard as he could. He started slowly at first then increased his tempo little by little.
"Fuck, Sans... Fucking shit, oh yeah." Grillby moaned and tilted his head back in pleasure while his hard cock throbbed rhythmically. Sans knew it meant Grillby was getting close to his point of no return.

"Mmmm," he moaned when he tasted hot, sticky pre-cum coming out of Grillby's tip. Suddendly Sans felt Grillby's hands push him away by his shoulders.

"I will not be accepting change no more."

He began to kiss Sans' neck while working on removing his clothes off starting with his jacket. Finally the last piece of clothing that remained were his shorts so Grillby kissed a trail down to Sans' hard cock while slipping off his shorts at the same time.

"Equal treatment equals same satisfaction." Grillby said. He gave the exposed blue cock a long lick from base to tip causing Sans to moan impatiently. Grillby wasted no time on taking the whole thing into his mouth and began to suck as hard as he could.

"Oh yeah. Oh Grillbz more please," Sans groaned softly when Grillby began to deepthroat, "that's it. Yeah."
Unexpectedly, Grillby removes his mouth and begins to lick Sans' tip, rubbing his thumb all over the sensitive area occasionally. He begins to continue his sucking by only focusing on the tip and sharply wiggling his head when necessary.

"Grillbz please," Sans begged now that he felt desperate.

"What?"

"Please."

Grillby smiled, "please what?"

"Me. Please me." Sans laughed at his own joke. He was later joined by Grillby.

"You clever piece of shit." Grillby finally said after catching his breath.

He grabbed Sans by his hips, sat on the nearest chair, and forced Sans down on him, shoving his hot rod inside Sans.

"Oh fuck, Grillbz." Sans threw his head back and groaned at the sudden feeling of Grillby's hard cock inside his tight asshole.

Grillby wasted no time on bouncing Sans up and down. His grip on Sans pelvis increased as the pleasure was building up. Sans breaths were fast and loud, he opened his mouth to take more necessary oxygen.

"Oh Sans. You're so tight. So tight it's so... good."

"Ah... Ah fuck, Grillby... Oh, you're so hot... And big."

His drool was now dripping down his jaw to Grillby's skin causing the thick blue fluid to blend in with his fiery sweat for one second then sizzle and dissolve into the air.

"Fuck... Ah... Ah... Grillby I... I feel it... Coming." he couldn't laugh through his fast hard breaths. All he could do was to open his drooling mouth to show a smile.

"You still haven't... Paid in full. So... do it."

"I need some... financial aid, Grillby."
Sans thrusted his hips up to rub his blue cock on Grillby's covered pelvis to give him the hint. In which Grillby took it by taking a hold of Sans's dick and then janking it up and down as fast as he could.

"Ah, fuck!" Sans yelled at the sudden increased sensation of pure bliss, "faster, Grillby."

Grillby increased his speed on both his hips and hand. After two minutes of work, Sans finally let it all out. Spreading cum all over Grillby's exposed torso and some on his own ribs.

"Oh yes!" Sans finally said after he came down from his high.

Grillby was about to let himself out of Sans but was stopped when Sans bounced on him again.

"We aren't finished, Grillbz. Remember, the costumer is always right."

"Sans..."

"Equal treament equals same satisfaction."

Grillby burst out laughing which made Sans smile at his only audience.

He began to proceed on his bouncing after Grillby finished laughing.

Not long after, Grillby finally climaxed inside Sans. Both moaned loudly at the feeling of release and the feeling of the release inside.

"Well... Do I still owe you?" Sans said when he laid his head on Grillby's chest.

"No, it's all paid now. But please make sure you do for now on, I'm serious."

"Hi, Serious, I'm Sans."

"Whatever."

Both leaned in for a long kiss. Little did Grillby know that Sans was now given the idea to purposely not pay his tab (most of the time).