(Warning: There's gonna be fluff? I think that's what it's called? Let's just call it fluff k?)
Y/n's P.O.V
I was on top of something warm I mean REALLY warm and there's something I can't describe... yet... I blink my eye a few times adjusting my view and saw Sans beneath me his eyes wide open in shock I... I WAS ON TOP OF HIM!?!
I quickly jumped out of bed expecting the cold floor to hit me but it didn't instead I was lift up from the ground and back to bed with Sans on top of me he huffed really deep.
"S-Sans? Wh-what a-are you d-doing?" I asked a little confused about what he is doing.
"S-Sorry Y-Y/n but I'm on heat~" he said it with a deep husky voice.
"Wh-what do you mean by heat?" I asked confused.
"It's s-something that we s-skeletons do e-every year and I need h-help with it p-please could you h-help m-me with i-it?~" he said.
"O-ok if it will help you with your 'heat'" I said smiling a little.
FLUFF! (Or whatever it's called 🐶🐱🐹🐰🐼🐨🐯🐻🐭)
Narrators P.O.V
Sans started licking Y/n's neck finding her sweet spot in an instant making Y/n moan a little.
"S-Sans wh-what is th-this f-feeling?" She said holding tight on the bed sheets.
"It's called 'Love'" He said grinning while continuing biting Y/n's sweet spot leaking out blood.
"W-well it f-feels go-aahh!~" She moaned louder Sans quickly and roughly clank his teeth to her soft lips.
Y/n gently put his arms around Sans neck for support while she blushed F/C Sans enjoyed the kiss while it last and proceeded to her neck licking the blood out leaving a mark on it.
"Now everybody will know that your mine~" He said proudly and proceeding to the fun part.
Sans started unzipping his jacket but was stopped by a door smacked down to the floor revealing an angry and surprised Papyrus.
"SANS WHAT'S THE MEANING OF THIS..... THIS....." Papyrus said blushing like a tomato.
"Hey Papy! I was just helping Sans with his 'heat' thing!" Y/n said proudly while Sans was blushing like a tomato too...
Papyrus quickly snatched Y/n out of Sans grasp and run out of the house as quickly as he could but Papyrus knows that his brother can go anywhere he liked which made Papyrus think stopping the whole way out of snowdin.
"HMMM.... WHERE DO SANS DOESN'T LIKE TO GO?" He said to himself while Y/n was thinking as well until she got an idea to where they would go.
"Papy! Papy! I know where we should go!" She said happily.
"WHERE HUMAN!?!" He said confused.
"Here hold my hand" She said while Papyrus was confused but hold her hand anyways.
Then Papyrus feel a little dizzy on the way and was blacked out....
~TO BE CONTINUED~

YOU ARE READING
Not All Monsters are Bad (UF! Sans x Experimented! Reader)
RandomYou've been experimented by your own brother to see what could happen if he tried a monster DNA in a human, No one wants to get experimented by him so you decided you'll be his test subject but it went terribly wrong......