~Undertale Oneshots Gone Lemon~

Geno X Nightmare

"Love and lust lead to mystery that one cannot unsee."

Sans from underswap was throwing a surprise birthday bash for dream. He was running late and needed some help so he asked Geno if he could get into contact with Dream's brother Nightmare.

Nightmare however, had completely forgotten about his brothers party, and had been hanging out with death in his AU. "I gotta go reap some souls in underfell, later you sack of depression." Death says before he disappears through a portal. Nightmare smirks a bit and turns around to be face to face with be Geno. "Holy shit! Where the fuck did you come from!?" Nightmare exclaims. "Um, its your bro's birthday today and I was sent to get you." Geno explains. "Why should I care, dudes turning a whole year older; woopty do..." nightmare says as he rolls his eyes.
Eventually Geno convinces nightmare to at least get his brother a gift. As they shop around all the different snowdins', Geno begins to get fidgety and anxious. The last store they visited had the perfect gift for dream: a charm bracelet with some clouds on it. Nightmare looks at it apprehensively and says "I guess this one looks nice." A good response, considering that this was the 5th store they had been to.

Geno had been very talkative up until the third store they visited, and his movements had become strange. Knowing that Geno probably had some wrapping paper at his AU, the two headed over to the Anti-void.

As soon as the two arrived Geno offered Nightmare a drink, whisky of course was Nightmare's pick. Geno poured the drink into a glass, his hands shakey as he did so. Nightmare knew something was up with geno, this was strange behavior for the guy. "Geno, are you okay? You don't look too good." At last, he couldn't hold it back anymore; his heat took him over.
"Hey, Gen-whoa!" Geno pounced on nightmare, a hungry look in his eyes. "Geno?" There was no response, just a low and monstrous growl. Nightmare was pinned down and unable to move; he didn't know why but he found this behavior of Geno's very alluring.
Geno tore Nightmares black robe off and eagerly grabbed hold of the soul that lies underneath. At last he spoke "Bend. Over. Now." out of curiosity, Nightmare did not obey. His punishment? A scratch to his soul. The painful expression on his face fueled Geno's heat. At the snap of his fingers a rope appeared and tied itself around Nightmares naked extremities; as well as a blindfold that bound itself around his skull. He was forcefully flipped on to his stomach by the entranced Geno.

Exposed and confused Nightmare cried out for help. But nobody came. Geno stripped himself and placed Nightmares soul in his mouth. Without warning Geno thrusted his whole length into the screaming skeleton. The screams were soon replaced with involuntary moans of pleasure. Geno took the now soaking wet soul out of its cage and began to rub it harshly, threatening to make it burst. Pain and pleasure flowed through nightmare, his breathing harsh and his energy fading. He spoke softly "please, le-let me go!" It was no use, Geno was all but lost in lust.
He tired of this position and flipped Nightmare upside down, exposing a fully erect ecto dick. Geno began to pump nightmares length while slowly sliding himself in. There were more screams of pain and pleasure as Geno quickened his pace. His thrusts became sloppy and soon enough the two skeletons were a mess of moans. Moments later Geno spoke in a cold and blinded manner, a careless warning. "I'm cumming for you pet!" Scared and helpless Nightmare begged "Geno! No don't...!" It was too late, Geno released his seed in the unfortunate skeleton. Tears began to swell in Nightmares eyes; The pain forced upon him was too great.
Humiliated and hurt, Nightmare made to escape his captivators' domain, forgetting he was tied up and unable to see, failed to escape. Pleased with his mess, Geno made his way to nightmare and removed his blindfold. Using his magic he moved to the couch and fell asleep next to his abused friend.

Hours had passed and Geno began to stir. "Hm, what...what happened? Why do I ache all over?" Just then he noticed Nightmare, and found himself and his friend to be naked. Blush quickly spread across his cheeks from embarrassment. Nightmare had been looking at him whilst he woke, his face full of terror. Geno saw that nightmare was bound by ropes and motioned to remove them, however nightmare only shyed away from his friends touch. "What happened to you? To us?! Are you okay?" The questions stirred in his head; he tried to place what happened, but was unable to recall what had occured. He did the only thing he could think to do...He fashioned a robe for Nightmare out of glitches and untied the ropes that bound him.

There was no hesitation from nightmare, he grabbed his new robe, his brothers birthday gift and with one last look behind him
disappeared.