Set after Sans unlocks his Elemental magic.

It was lunchtime when Mina and Denki found it. An online challenge where one person in a couple tries to make the other all flustered and blushy. Sans had his head on the table, fast asleep, and Katsuki had his hand on the back of Sans's head, gently running his fingers through his hair.

Mina - "Hey Bakugo!"

Katsuki - "What?"

Denki - "Take a look at this!"

Denki slid his phone over to the more explosive blonde with a cheshire like grin.

Katsuki - "That's stupid. What's the point?"

Mina - "Stupid? What, scared none of it will work on your beloved?"

Hook -

Katsuki - "The fuck did you just say to me?!"

Line -

Denki - "Don't worry about it dude, if you don't think you're romantic enough to pull it off, there's no need to force yourself."

Katsuki - "I'm the most romantic one at this damn table! I can do every single one of these stupid prompts and make him a stuttering mess!"

Sinker.

Denki/Mina - "Prove it!"

Katsuki - "Damit I will!"

Katsuki looked over the prompts again, more seriously than he did the first time.

Grab them by the waist and pull them in for a surprise kiss

Prolonged Staring

Call them by their first name and your own last name

Cutesy Nickname; ex:: My love, Babe/Baby, Wife/Husband/Partner, Prince/Princess

Take a nap on their lap

Promote eye contact by grabbing their chin and making them look at you

Cheesy Pickup-up Lines

Random Braids

Kabedon

Pocky game

The bell blared, barely rousing Sans from his nap. He stood up to fully stretch and yawn.

Sans - "Mmh, GZ, what time is -"

His question was cut off when his boyfriend's arm wrapped around his small waist and pulled in into a deep kiss for them being in a quickly emptying cafeteria. His face lit up bright red and his eye lights were blown into large spheres.

He became dead weight pretty fast and leaned himself against Katsuki. He was vaguely aware of the wolf whistling coming from their table, but as soon as Katsuki separated from him, thoughts couldn't seem to form. Sans had to slung over Katsuki's shoulder so they wouldn't be late for class.

Mina - "One down, nine to go blasty!"

<~>

Sans was sitting in the library. He was invested in a book focusing on his new world's astrology. Constellations, planets, blackholes, wormhole possibilities, dark matter, nebulae, etc. When he was a small baby-bones, Grillby would talk about how beautiful the stars were on the surface. How the pinks, blues, and other pastel colors gave way to inky black-blue skies littered with stars and the many moons the surface had.

Katsuki - "Hey Richter, what're you reading?"

Sans - "A really cool book about astrology. Did you know wormholes are an unproven phenomenon? They could potentially exist, though they haven't been observed and theories state they might not have the stability to form in the first place. Also the picture of the...fast radio bursts, kinda reminds me of shooting neurons in the brain. Veil remnants are so beautiful, I wonder if I'd be able to see them from my telescope...no, it's remnants of exploded stars, if that happened near Earth, this planet'd be destroyed."

Sans rambled about space phenomena as Katsuki sat next to him. The blonde leaned his head on his hand and smiled warmly. His eyes were shaped like stars. One of Katsuki's favorite things about Sans was his eyes. They always conveyed how the former monster felt. Stars usually meant excitement or unbridled joy, exclamation points meant shock, so on so forth. The more Sans spoke, the more fondly Katsuki looked at him.

Sans's rambling was cut short when he looked up at him. His cheeks were dusted with pink and he covered his face with his book.

Sans - "Why...are you looking at me like that?"

Katsuki - "Because I have the sole privilege to see how cute you get when you're excited about something."

Sans covered his cherry red face completely with the book. Katsuki laughed lightly but sported his own blush when Sans quickly stole a cheek kiss.

<~>

Modern Hero Art or whatever, was Sans least liked class. Midnight taught it, and she tried her best to make it interesting, but it was unsurprisingly dull. The only plus was that there were two person desks that they got to choose the seat with.

Katsuki made it well and clear to sit with Sans in every class. Not like anyone, especially him, minded, he got to cuddle on Katsuki's side or hold his hand under the table whenever he wanted.

Katsuki - "Bakugo..."

Sans's pre-nap rest was interrupted. Katsuki was smiling to himself while muttering his family name. It was a little unnerving.

Sans - "Kats, you good?"

Katsuki - "Bakugo W. Sans, has a nice ring to it doesn't it?"

Sleep be damned. Hood was pulled tightly over his head and his grip on Katsuki's hand tightened.

<~>

Sans groaned in the library. It was after school and he, Eijirou, Hitoshi, and Denki were studying. Eijirou was helping him with his history and it felt like his brain was being fried.

Hitoshi - "How about we take a break before Denks short-circuits and fries us. I'll give get some drinks from the vending machine."

Denki leaned on the table with his arms stretched in front of him.

Denki - "Thanks babe! Hey Sansy, do you call Kacchan any pet names?"

Sans - "Pet names? Like for dogs? I'm not good at that, Mayo was a joke, but the name stuck."

Eijirou laughed and ruffled Sans's hair.

Eijirou - "No bro, pet names used in this context are terms of endearment. Like uh, babe or um...honey. Something cute to call them."

Sans - "The only nickname I have for him is Ground Zero. Does that count?"

Denki - "I mean, technically, but in this instance I'm saying no."

Katsuki - "Sorry I'm late, hag needed help moving shit."

Sans - "One second....Okay, Hey sweetheart."

Denki choked on the coke Hitoshi gave him and Eijirou was cackling. Katsuki's cheeks were tinted pink as was Sans's, but Katsuki leaned over with a smirk.

Katsuki - "Well, hey to you too, little darling, looking gorgeous today, now aren't we?"

Sans's face grew more and more red the more Katsuki went on. Said blonde snickered and pulled Sans close so the smaller could face his face in his chest. He pressed a firm kiss to his temple.

Katsuki - "Don't start something you can't finish, Richter."

<~>

Katsuki was uncharacteristically exhausted. He couldn't get much sleep, he and his parents were keep awake because the damn neighbors were having an obnoxious party complete with booze and loud music. The majority of teachers were called away to deal with a variety of major crimes; ranging from kidnapping, bank robbery, and there was at least one bombing. So Nezu let them all have a three day weekend.

Sans had his house all to himself. Eijirou and Mina went on a date, Ichika had to go into the office to help a couple of her younger coworkers, Natsumi had work, Grillby had work, Asriel had school, and Hitoshi had a date with Denki. Shota and Hizashi were dealing with some hero job or whatever. So logic logicking, Katsuki was invited over. His poor pomeranian was barely walking in a straight line, he was so tired.

Katsuki - "Richter?"

Sans - "Hey GZ, you sleepy?"

Katsuki - "Hmm. Fuck'n neighbors had to throw a massive party and kept it up all night."

Sans - "I'll let Ma know and she'll pop by to put an end to it. Wanna take a nap with me in the meantime?"

Katsuki pushed Sans back onto the couch and laid his head on his stomach. His arms wrapped around his middle and he was out. Sans was a violent red mess but was snoozing within a few minutes right behind him.

<~>

Sans was pissed. Eijirou kidnapped him and then abandoned him in the park, AT NIGHT! They were in the middle of a prank war and Sans was gonna dye his hair white as payback. He thankfully slept with his phone in his pocket.

Sans smiled at the little heart Katsuki sent him. He could already see the orange of Katsuki's black and orange flannel pajama pants. It looked like he jumped out of bed and rushed down from his house.

Katsuki - "Hey Richter, come on, you're sleeping at my house, you can borrow one of my uniforms for school tomorrow."

Sans - "Thanks, but I think I'll stay home from school tomorrow."

Sans was fuming and plotting all the ways to get Eijirou back for this; the hair dye wouldn't be enough. An index finger and thumb gently gripped his chin and made him look into Katsuki's eyes.

A worry crease was formed in between his eyebrows and his eyes held so much warmth that it stalled his brain.

Katsuki - "Are you feeling okay? It's pretty cold out here."

His face almost glowed from how pink it was.

Sans - "I'm fine! Just tired!"

Katsuki - "Still, I don't want you walking with no shoes. Assholes don't pick up after their dogs."

He was hoisted into Katsuki's arms, bridle style.

<~>

Sans was invited to hang out with Katsuki. Sans was dressed up by his best friend herself. Mina picked out a baby pink, spaghetti strap sundress, a thin sage green cropped coat, his obnoxious sneakers, light mascara and lipgloss, and two pink barrettes holding hair from his eyes.

Sans was walking closer to the address sent to him from Katsuki's phone. Something about it was weird though.

Katsuki's typing was informal, not the formal slightly aggressive way he always used. Sans didn't know what to expect. It didn't read like something Katsuki Would write.

??? - "Hey cutie~ What's your name?"

A green-haired guy a little older than Sans pulled up right beside him and wrapped his arm around his waist. Sans could admit he was objectively very pretty to look at, but it sleeved him out a little.

Sans - "Not interested."

??? - "Aww, don't be like that~"

Katsuki - "Murata! Give me my damn phone - Richter, what're you doing here?"

Sans gawked at Katsuki's unusual well-dressed appearance. He was wearing a light orange muscle shirt with a black vest, black dress pants, and black dress shoes.

Murata - "Just saying hello to this little strawberry."

Sans immediately shot a dulled bone into his stomach and retreated behind Katsuki.

Murata - "Feisty. I like it~"

Katsuki - "Sans is my boyfriend. Get lost or 'll have your job."

Murata - "Ugh, why're all the cute ones guys? Keep him, I gotta shoot in three. Laters. Oh wait, Kats, do the thing!"

Katsuki - "Dammit, fine! Richter?"

Sans was very confused by the interaction.

Sans - "Yeah GZ?"

Katsuki sported an embarrassed look as he smirked at him.

Katsuki - "Did you hurt yourself when you fell from heaven?"

A small blush and giggle escaped Sans before he could stop it.

Sans - "No, but I scrapped my knees coming up from hell."

Mina prepared him with a bunch of responses for pick-up lines like that.

<~>

Sans was utterly gobsmacked. Mina kept finding tiny braids all throughout his hair during their spa day. Worst of all they were only found when the comb snagged on them.

Mina - "And another one, I'm up six braids, what the heck is going on here? The braids set us back, I have to leave soon, sorry Sans."

Sans - "It's fine, Katsuki's actually dropping by so I'm not too disappointed."

Mina - "Ohoo~ I bet, far be it from me to keep your big strong lover boy."

Sans helped his best friend pack up her stuff just in time for Katsuki's arrival. They spent a while cuddled on the couch watching movies when Sans woke up. He didn't realize he even fell asleep.

Gentle tugging from his scalp made him lift his hand to grip a loosely braided lock of hair.

Katsuki - "Good nap?"

Sans smiled and his cheeks picked lightly.

Sans - "Need more sleep."

He turned his head and snuggled closer into Katsuki's chest.

<~>

Sans snickered at Eijirou's excessive planning of buying Mina a present. They were both at the mall for whatever reason and decided to buy their s.o's a present. Sans got Katsuki a muscle relaxant cream for his back and legs and a small hotsauce variety pack.

Eijirou was all over the place not knowing what to get.

Sans tried to help him, but Eiji would've keeled over in embarrassment going into a women's undergarments store. So he was gently ushered toward cosmetics and clothes.

Eijirou - "This is impossible! How'd you decide on stuff so quickly?!"

Sans - "Well, Katsuki is my boyfriend. I know what he likes. He works so hard so the cream will definitely be useful. I love him so much that I don't want to to see him in painNN -"

Sans was yanked backward and slammed into a wall behind him. Katsuki's face was dark red and Sans wasn't any better. Very light steam was rising from his face and hair.

Eijirou - "Bro! A kabedon in public! So manly!"

<~>

Denki - "Oh Sansy~ Wanna play a game?"

Sans - "What game?"

Denki - "Two people bite on a piece of pocky and they both munch. The first person to pull away wins!"

Katsuki - "Like hell he's playing that stupid game with you, dunce face!"

Sero - "Yeah Denks, clearly he wants to be the one to play with him."

Denki and Sero shared evil grins as they forced Katsuki to stand in front of Sans. The chocolate covered end of the cracker was shoved between his lips and Katsuki bit on the other end. Sans's face almost caught flames as soon as he realized what the game entailed. He was frozen in place as Katsuki quickly cleared the distance between them. Soon they were a single bite away from each other.

Katsuki looked him dead in the eyes as if daring him to make the final bite. Sans quickly pulled away, stole the last bit of cracker, and gave Katsuki a proper kiss before eating the last bite.

<~>

Katsuki - "There I completed the damn challenge, now fuck off dunce face!"

Vote, comment, and have a fantabulous day 💖💖😊😊 
2423 words 
Enjoy 

Little rushed at the end, but the writer's block was strong with this one