Fell under the covers **wink** (Undertale Lemons)

Sans x reader Happy fellday kid

It was cold and dark morning when I woke up. A day like this is very rare on such a exciting day!
To day was my birthday!

Or my so called 'fellday'
It's when I fell down here,

I looked up at the ceiling for a bit, I didn't notice the whole monster family, I so called them, to come sneaking in.
When I looked back down I swear I almost had a heart attack!
"SURPRISE!" Everyone yelled and laughed as I had a terrified look of horror on my face.

"Happy fellday human!!" Papyrus said and put a hand made hat on my head with glitter and paper hearts all on it.
"T-thanks.. Papy...?" I said kind of weak and even gave a weak smile.

"Oh! happy birthday and fellday my child!" Toriel said and hugged me tightly. "I have a present for you!" She said and smiled and took a present from her oversized sleeve and it was a glowing glass heart, the glow was a soft red and I smiles at it. "Thank you goat mom!" I yelled and hugged her.

"Uh.. Hey kid.. I have a present for you, but.. Uh.. I can't give it to you until tonight.." Sans said awkwardly and gave a grin.
"But, have a DINO-mite birthday" sans said and winked, making me blush a soft pink and he drank his ketchup and left.

Why tonight? Why not right now? Is it going to be embarrassing?! Is he going to tell a secret to me?!
I thought and blushed again.

Everyone else just gave me cards, but my mind was always focused on the present sans is going to give me tonight.
Everything did go quickly, the cake.. The party games.. The glittery pasta...
You know normal things down here.
I waved goodnight to everyone, and papyrus said he was going to have a slumber party with mettaton, so I could have fun by myself.

I sighed and closed the door.
The silence was very loud.
I walked slowly up to my room.
I opened the door and walked in leaving the door open and I stumbled to get to my bed.

I stooped before I got to my bed and I bent down to get my pjs. I picked shorts and a tank top. I took off my clothes leaving me in my underwear and my bra, I took my bra off only to leave me in my underwear. When I was about to put on my tank top I felt someone starting at me. There eyes locked onto my whole body, I felt my stomach turn, or another term I can use, I felt my sins crawling on my back.

I turned around covering my breasts with my tank top and I saw the blue light from his eye staring at me.
"You must be dying to know what your surprise is.." He said carefully closing the door and locking it.
The click from door made me get goosebumps.
"P-please sans I'm changing.." I said and quickly regretted it.
"That's even better (Y/N)" he said and grinned when he walked to me slowly.
I panicked and pushed him back.
"No!" I yelled and try to smack him but he dodge. I was surprised.
"What? You think I'm going to stand here and take it?" He said and put his hands on my shoulders.
His boney fingers rubbing my shoulders and was leading down to my chest.
"No no! Get away!" I yelled like I was 4
And pushed him away again only to know that he grabbed my tank top and I was there covering my double (cup/S)'s
"I don't want to hurt you little girl.." He said and the lights turned off.
"Sans! Stop joking around-" I was cut off by sans as he picked me up making my legs go around his hip bone and making my hands go around his neck.
"ACK!" I screamed.

I blushes madly as my breasts were up against his face.

Sans just kind of stood there until he dropped me on a pillow and him on top of me and he kissed around trying to find my sweet spot.
And right when he found it, I went wild.
My arms around his head and my legs around his hips and moaning quietly.
"Let's turn this into a fun little game.." He said suddenly in my ear which made my sins go up and down my back almost tickling me. "This game will be called 'don't move' and if you win, I won't bother you, but.. If you loose.. I can fuck you all night.." Sans said and his glowing eye was right in front of mine. "Ok your mark.. Get set.." Sans said and pinched me.
"Ah!" I squeaked and sans went down on me or chests together and his wet blue tongue licking and trying to suck on my sweet spot. I almost made a sound but I just moaned in my head as I was fighting the urge to move. He growled and he pulled away.
"You want me that badly?" He said and chuckled.
I guess he knew I was fighting the urge and I couldn't react, so I just looked away blushing but not moving me head.
"Fine.." He sighed and pecked my shoulder with kisses then to my mouth, traveling over my jaw line, on my neck, then when he came to my breasts, he squeezed them tightly hopefully to get a noise, or a movement.
My eyes widened and I made a face and squeezed my hands cause of the pain. Sans squeezed tighter and I stuck my tongue out and kicked him, he dodged again, he grabbed my foot,  "I'll let that one slide.." He said And licked my foot and my leg and kept traveling down.
He licked my inner thigh only making me feel super weird and bite my lip as he moved closer and closer to my kitty.

I bit my lip harder as he licked the area around it and made me super wet,
Come on! Just 2 inches!
But he wanted to make me super wet.
He licked lightly over my kitty, only making me into a panting mess,
Come on! Harder! Harder!
"Your so wet.. I can taste it.." He said making every word he said blow across the top.
Making me arch my back on accident.
Can't take it anymore! Please!
He was in no rush to make me pleased.
"Go on.. Beg me... Beg me.." He said in a whisper as kept repeating licking lightly.
"Please! Please! Harder! Harder!" I yelled holding his head.
"Harder? You want me to go harder huh? Huh?" He kept teasing.
"This is the worst fellday ever!" I yelled and pushed his head lightly.

He imminently started going harder and sticking his long blue glowing tongue inside me.
"Yes yes!" I yelled as he repeatedly went in and out, in and out, in and out.
I found myself thrusting against his tongue.
He kept licking until I yelled in pleasure, and that's when he knew it was time.
He climbed over me with his tongue out. I looked into his eyes waiting for him to say something, until I felt his large cock jam inside me.
"ACK!!" I yelled as he thrusted back and forth and licked my sweet spot on my neck. Faster and faster he went thrusting, and pulling my hair back as he wanted to go deeper inside.
I thanked the lord that he even put his cock inside me.
I couldn't think of anything right now, my brain was only focused on the fiery goodness that kept my body going, I felt every 50 calories getting burned off as he thrusted even deeper, and deeper.

At this rate I couldn't hold anymore, I just couldn't. i think sans noticed my face that meant can't hold it any longer!
And he grunted as he went deeper and faster then covered my mouth
I screamed as I had my orgasm, and him filling me up with nice warm cum.
He pulled out and lied beside me.
"H-happy fellday kid.." He said as I painted like crazy.
I curled up beside sans as he twisted my (H/C) hair.
"By the way.." He said making my blood run cold and said in a raspy voice making my ear numb.
"You lost the game."
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Yay I finished it.
Took three days to figure out how to write lemons, but I did it!
Yaaayyyy
See ya mints~🎿⚗