Requested by XxEpicBruhxX, here ya go!
~Backstory~
Cross had been sitting with Chara in the empty void he once called his home, his AU. Suddenly, a portal appeared and sucked him in. It dropped in into a snowy forest. He heard someone behind him. He whirled out and saw a skeleton with a blue jacket. The skeleton reached his hand out to Cross.
???: "Don'y you know how to greet a new pal? Especially your own species?"
Cross reached out his hand. A loud 'PFFFFFFFT' was heard. The skeleton raised his hand and Cross saw a whoopee cushion.
???: "Heh, old whoopee cushion in the hand trick. Well, I'm Sans. Sans the skeleton."
Cross: "Oh. I'm Cross. Nice to meet you."
Sans: "Nice to meet ya too, Cross. So, mind telling me why you're in the middle of Snowdin forest?"
Cross: "Well, uh... ya see uhm... okay, this sounds weird, but hear me out, ok? I was in my AU that got erased and got sent here through a portal."
Sans: "Oh. So you're another AU of me. Got it."
Cross: "Wait wha-"
Sans: "I know a lot of AUs. Since you're kinda stuck here, you can stay at me and my bro's place."
Cross: "Really? Thanks!"
Sans: "No prob buddy. By the way, who's your pal?"
He pointed to Chara. Both Cross's and Chara's eyes widened in surprise.
Cross: "You can see him?!"
Sans: "Uh, yeah... is that not normal?"
Cross: "You're the first monster that can see him besides me!"
Sans: "Alright. Now then, let's go. I know a shortcut."
~Back to present~
~3rd PoV~
Ever since Sans and Cross met, they were friends. They had become friends quite quickly. They always told puns to each other, and enjoyed each others company. They both secretly had a crush on the other, but didn't want to tell the other, as they both thought if they did, it would ruin their friendship.
~Timeskip 3 weeks~
~Sans's PoV~
'Worthless.'
Cut.
'Mistake.'
Cut.
'Cross will never love you! You so ugly!'
Cut.
'Just go die already!'
Cut.
Suddenly, a hand stopped him from cutting. He looked up and saw...
Sans: "C-Cross?"
Cross: "Sans... why are you doing this to yourself...?"
Sans: "Because I'm useless, and weak, and I can't do anything right-"
Cross wrapped me in a hug. I started to sob on his shoulder. After a while, I stopped.
Sans: "S-Sorry Cross, I got your jacket wet..."
Cross: "It doesn't matter. You don't need to cut yourself. Because I think you're great, Sans. I think you're perfect. I...I love you, Sans."
I never thought I would hear those words as soon as he said it, he kissed me. I kiss back. We both pulled apart.
Cross: "I-I'm sorry, I shouldn't have done tha-"
Sans: "You don't need to be sorry. Now, cuddles."
Cross: *Chuckles* "Alright."
They turned the TV on and watched a movie. After the movie, Cross carried Sans bridal style to his bed and put him on it. He pecked Sans on the lips and said,
"I love you, Sans. I hope I can make you happy."
Sans opened his eye sockets and hugged Cross.
"You already have."

YOU ARE READING
Classic Sans x AU Sans Oneshots (Requests closed at the moment)
FanfictionEh, why not! Cover is mine! Took me a while to make it, but I know it looks bad. U-U Ratings: #1 in Dussic as of 8/3/2020 #50 in Undertale as of 8/28/2020 #6 in Classic Sans as of 8/25/20 #25 Nightmare Sans as of 8/25/20 #48 in Error Sans as of 8/25...