Quick note in this one shot you are on the surface and Alphys with some help managed to revive Asriel and Chara
Third Person POV

"Wanna have a bad time kid?" You giggled at the skeleton before you and showed your game face.

"Bring it!"

Swish! SMACK!

You and Sans laughed as Pap shouted in confusion. You couldn't stop laughing as Pap lost the bet and had to wear Frisk's ballerina tutu for the rest of the day

Sans, who finally stopped laughing, looked at the still standing Jenga puzzle then turned to your current state.

He couldn't help but smile as he heard your melodic laugh and gave out a soft chuckle.

"Atleast I got me some 50 bucks." He murmured then thought of an idea. He stood up, making you stop and look at him with confusion.

Sans smiled and held out his skeletal hand, in which you gladly took and stood up.

"How about some nice cream kid?" You grinned as your eyes sparkled, something Sans always loved to see, and you nodded your head eagerly.

"Did somebody say NICE CREAM?" Three voices shouted as you heard footsteps nearing the living room.

"We wanna come!" You laughed at the two humans and goat child's behavior and motioned for them to come.

Sans, who already went outside smiled at the sight of you giving Frisk a piggyback ride and the five of you started walking.

"Alright guys you can go play at the playground but go exploring tomorrow, okay?" You asked as the children nodded and ran to the swingset with their nice creams.

You and Sans sat at the bench that was under a tree near the playground and ate your creamy goodness.

You gave out a sigh of happiness and laid your head on the big boned skeleton's shoulder blade.

Sans' face erupted into blue hue and sweat nervously as he saw Chara and Frisk looking at them with a grin of mischief.

The two motioned for Asriel to come with them and quickly ran to hide from the short monster's point of view.

Sans just looked around and tried not to shift to much because you fell asleep.

"SANS AND (Y/N) SITTING IN A TREE! K-I-S-S-I-N-G! FIRST COMES LOVE! THEN COMES MARRIAGE! THEN WALK THROUGH THE PARK WITH A BABY CARRIAGE!"

The both of you jolted up as the trio sang (screamed) behind you.

Because of this, you two fell off the bench and were laying beside each other.

Sans couldn't do anything but chase them around playfully as they ran, giggling happily.

You grinned and decided to join their game and caught Asriel in your arms.

"MEEEEHHHH!!!!" Everyone stopped for a second then laughed, continuing the game.

A lot of people who were in the park, smiled and laughed at your group's antics.

"They can sure make anyone feel like family."

A few children of monsters and humans joined in and ended up glomping Sans to the ground as you laughed, sitting on the grass to rest.

After the game of tag, all of you left and set the three to bed. You both went out after talking to Toriel, with Papyrus, who was still wearing the clothes.

You and Sans snickered as he tripped again, joining hands and walked home together with a tripping ballerina.