warnings: gay, incest, threesome
(US stands for Underswap; frankly i find the swap versions of sans and papyrus hotter than their regular ones)
this story is inspired by lizherubones's art. if you've never seen their work and like this story, I HIGHLY advise you check it out.
----------
Papyrus closed the door of his room behind him, stepping out into the hallway. He grabbed a cigarette from his pocket and placed it between his teeth, not lighting it (Sans was always complaining that the furniture smelled like smoke (plus, Papyrus liked having something in his mouth)).
He rolled the cigarette between his teeth and walked across the landing, headed towards the stairs, but he stopped in front of Sans's room. Behind the caution-taped door, he could hear something.
Curious, Papyrus tilted his head toward the barely open door. It was dark in Sans's room, but he quickly identified the source of the sounds- his brother getting dicked.
Sans's blue dick throbbed as you thrusted into him. The skeleton's magic genitals and tongue emitted a faint glow, bathing the two in a soft light as they fucked.
Papyrus's skull lit up orange with blush, but he couldn't look away. It didn't seem like the two noticed him watching- they were too preoccupied with each other, moaning and grunting on the bed. He found his hand reaching toward his crotch, slowly unzipping his shorts, never taking his eyes off the sight of his brother's ass getting pounded.
Papyrus gripped his now erect dick with his hand, slowly masturbating while watching you fuck Sans. The younger skeleton moaned, gripping the sheets of his bed as your dick slid in and out of him. Fuck, Papyrus wanted to be you. To fuck his brother. His ass just looked so tight. Yours wasn't bad, either.
It was hard to tell with how you were breeding Sans, but it looked like your dick was pretty big, too. Sans certainly seemed to be enjoying it. Papyrus could see the faint shape of your dick sliding in and out of his brother through his ectobody.
Papyrus leaned against the door, forgetting that it wasn't stable. It swung open and he fell to the ground inside. Your head swiveled around, and Sans's eyes widened.
"Uh- Papy, i-it's not-" Sans started, but then he noticed Papyrus's massive dick standing tall. The brothers were both blushing profusely, unable to take their eyes off of each other's bodies. You were the first one to break the silence, your dick still inside Sans.
"Don't just sit there, dude. Come help me fuck your brother."
The older skeleton looked at his brother, whose face was as blue as a popsicle. Looking deep into his Papyrus's eyes, Sans nodded.
That was all the permission Papyrus needed. He got up, went over to the bed where you were still inside Sans, and stuck his dick inside as well.
"Ha~ ahh!" Sans moaned, gripping the sheets. Your breathing sped up. You'd never imagined you'd be rubbing your dick against Papyrus's inside Sans. Well, sure, you had imagined it (you were very horny), but you'd never thought it could happen.
The orange cock pressing against you was warm and thick- it barely fit alongside you inside Sans. Both skeletons released a shaky breath as Papyrus made it all the way inside his brother.
You smirked, feeling confident, and thrusted into Sans.
Both boys moaned in unison- Papyrus from the clenching of his brother's ass and the friction of your dick, and Sans from having two cocks inside him. It wasn't long before Papyrus joined you in moving too, rhythmically fucking his brother. The sound of your bodies rubbing and thrusting turned you on even more. You'd been close before, but now that both Papyrus and Sans were here, there was no way you'd last.
You gripped Sans's leg, speeding up, and Papyrus followed your lead. Sans's moans grew louder and louder, more and more lewd, until-
You couldn't hold back anymore. Your semen gushed out into Sans's ass, coating his insides and his brother's dick. The feeling of your cum on his dick pushed Papyrus over the edge too, and he came as well. Sans, full of two loads of warm seed, quickly followed, his body shuddering as he orgasmed.
The three of you collapsed together on Sans's bed. You and Papyrus's cum leaked out of Sans's ass, and it seemed like he loved it. You didn't say anything, laying together, breathing heavily. Words could wait.
YOU ARE READING
~Lusting~ Undertale X Reader Oneshots
Fanfiction!!! Does contain explicit content !!! A collection of Undertale oneshots. Feel free to request on the request page. Can be angst, Fem!reader, Male!reader, smut, fluff...
