Underfell Sans x Skeleton Reader

Making love (lemon/smut)

Warning: Lemon/Smut ahead don't like it, you don't have to read it. I'll put in a warning when it starts. Anyway enjoy!

This was terrible! This feeling was so terrible! Ever since Sans had kissed you yesterday, this feeling had showed up. It was making you crave for something that you didn't know. And this feeling had been the entire time you and Sans were watching this movie. He was sitting next to you, one arm around your shoulder, touching you. It was increasing every minute and at some point a faint glow had started coming from your chest, fortunetly hidden by your shirt, wich was also getting uncomfortable to wear. You were trying your best to hide this from Sans. Papyrus had left for today, so Sans and you were alone. The movie was half way, when Sans suddenly pulled you into his lap. This, sadly for you, worsened the feeling too much to bear and a wierd, silent sound escaped your mouth. It wasn't a surprised sound or anything like that, you had never heard a sound like that before. You were hoping Sans hadn't heard and it seemed like he hadn't. You just tried to calm yourself down but this was only getting worse. The glow in your chest had picked up brightness and your breathing was getting heavy. You were feeling so hot, you had started panting slightly. Your soul was starting to beat faster, causing you to clutch your shirt where your soul would be. "Sweetheart?" You heared Sans' quiet and concerned voice. "Y-yes?" you tried to cover it up and sound enthusiastic but it was only working partly. He placed you on the couch next to him, stopping the movie. You were hoping he wasn't going to question it. "What's wrong?" He questioned with more concern. You were going to tell him nothing but you couldn't, this was unbearable. Maybe he could help you get rid of it. "I-i'm f-feeling w-wierd." you managed to get ou between your shaky breaths. "What do you mean?" "I-i'm f-feeling so h-h-hot." He seemed to think for a moment before his eyes widened. "Are you in heat?" You looked at him confused: "W-what's heat?" His eyes widened again. "It's when a monster gets well..you know, like aroused." Now it was your eyes that widened. Was that really what was happening to you. "Want me to help you get rid of it?" Without thinking what 'help' could mean you nodded heavily. He smirked, grabbing you and teleporting you into his room onto his bed. You looked at him confused. What was he planning?

Lemon/Smut starts here!

Before you could ask, he pinned your arms next to your head. You were going to struggle but he leaned down and whispered into your non existent ear: "Just relax. I won't hurt you, i'll help you." His words made you relax a little, so you just relaxed your body, hoping he could help get rid of this so called heat. He leaned down more, pulling you into a deep kiss. You kissed back. Something brushed against your mouth, it was slimy and squishy. You opened your eyes, looking for advise of what to do now. Sans nodded, that slimy thing pushing a little more against your mouth, so you opened it. It slipped inside, exploring your mouth. Your magic acted on it's own, forming your own ecto tongue. Both ecto parts started dancing with each other, you trying to copy Sans clumsily. This went on for a little time, before Sans pulled away, letting you pant for air. He smiled at you, before dipping down again, this time to your neck. You felt a little kiss on your neck bone, it felt surprising you nice. More kisses followed on your neck. Soon Sans' tongue was dragging across your neck, making you gasp every now and then, it was feeling really good. But it wasn't satisfying this feeling. A small sting ran through your neck, making you squeck. He had bitten down slightly, not enough to leave any permanent damage though. He pulled away from your neck, after giving the bite mark a few licks. He let go of your amrs, you didn't move though. He tugged at your shirt, you hesitated but nodded, helping him pull it off. He admired your upper body for what seemed like hours, before finally moving again. He traced each one of your ribs with his finger. It made you shiver, feeling so good. It only increased when he used his tongue along with his fingers, massaging your ribs. Your legs were shaking lightly from this pleasure. You felt him move but you were distracted by this great feeling overtaking your body. He finished his work on your ribcage, sitting up straight. Just then you noticed your pants gone. When did that happen?! All you were in now were your panties. He placed his hand on your spine and started rubbing slowly. The pleasure irradiated through your body, with every move he maid his speed increased as well as your dufficulty to keep those wierd sounds in. Not long after he was now rubbing your spine pretty fast and every now and then one of those sounds would escape. Your body was tingling with pleasure. Your hands had been clenching the sheets for quiet some time now. Suddenly his movements slowed to a stop, pulling a little whine for more from you. He chuckled at your need, before tracing the edge of your panties, looking up at you for permission. Your need had increased by so much more, you nodded wishing for this desire to be fulfilled. He pulled them off, now leaving you completely naked infront of him. But before he continued, he got rid of his own clothing, except his boxers. For a moment you forgot all your need upon seeing his bones. Almost all of them were cracked and damged. You felt pity for him and were about to say something, when he shushed you with another kiss. "Don't worry about me, okay?" He said after pulling away. You just nodded. "Now then." He pulled your legs apart, exposing your naked pelvis. "Form it." You looked at him confused. What was he talking about? "Form your part." "What d-do you m-mean?" He looked at you confused, before giving you a comforting smile. "Do you know how to form an ecto body?" So that's what he meant. You shook your head. "Don't worry. I'll help you summon it, ok?" You nodded. He placed his hands on your pelvis, surrounding his two limbs in red magic. His magic activated yours, letting it collect a (f/c) smoke in your pelvis, before that spread out over your lower body, creating a female ecto body. You looked at it in awe, having no idea your magic could do something like that. It was (f/c) and going from your knees to your chest. Sans started caressing the newly fromed magic, wich was making you feel a little bit of pleasure. He moved his hands to your thighs and across your legs, wich were already laying on the bed, open, giving him a full view of you. He moved his hands inbetween your legs to your womanhood. He dragged his finger across your folds, making you gasp. He caressed your folds a little more, dragging gasps from you. After he got bored he moved to your clit. He could clearly see that you tried holding back: "Don't hold back. I wanna hear you moan." So that's what those sounds were called. His low voice broke your hesitation. That's when he started playing with your clit, touching, pinching and rubbing. Every touch was pure heaven, it was feeling so great. Unbelievably great. Your sounds were showing that aswell, forming louder and louder moans. He, again, slowed his movements to a stop. You returned to your panting, not feeling that pleasure anymore made you whine. You were craving for more, so much more. He made a devilish smirk and brought his head infront of your entrance. You were about to question his actions, when you felt something wet and slimy slide across your folds. His tongue. A loud moan escaped you. He started prodding at your womanhood and eventually pushed his tongue in. An even louder moan left you. He waited a little after he had pushed his tongue all the way inside and then he started moving it. Moans were escaping your mouth while he was eating you out. His tongue was filling you with so much pleasure. And that pleasure was making something build slowly and steadily. Like a pressure in your lower stomach. With every little move from Sans the pressure increased. That only doubled when he started rubbing your clit alongside his tongue. This was building the pressure twice as fast. It was so great, you wanted No! needed more of this. Your hands reached down, pushing Sans' skull stronger into you, feeling like you were going to explode. Sans quickened his pace, knowing that you were close. That did it! You hit your peak, arching your back and giving of your loudest moan. You came right in Sans' mouth. Your body relaxed, letting go of Sans' head. He sat up, licking the remaining liquid of his face: "Delicious~" You were a panting mess. You managed to calm down a little, feeling the heat die down a little but not disappear completely. You felt a little exhausted. "How was that, sweetheart?" You smiled at him weakly. "We're not done yet." He grabbed his boxers and pulled them down, showing his long red and hard member. He weakly lifted yourslef of the bed, sitting up after he had signaled you to go to him. You shakily craweled over to him, stopping when you were infront of him. "I would like to feel good too, okay sweetheart?" You nodded. He did help you and of course you wanted to repay this favor. He pointed at his member and then at your mouth. It took you a little time to understand but after that you opened your mouth, taking it in your mouth. It didn't fit in fully, so you grabbed the rest with your hand. He moaned slightly, telling you you were doing the right thing. You started moving your head while strocking the rest of his length. He had his head thrown back, back arched and moaning. Yup, you were doing good. You quickened your pace, sucking aswell. His moans increased. His member was throbbing in your mouth, he was close to his limit. Suddenly his hand was on the back of your skull, forcing his whole member into your mouth. It surprised you but you continued sucking anyway. He was cursing while moaning. After a few more thrusts he released inside your mouth with a loud moan. He let go of your skull and you pulled away. Not knowing what to do, you swallowed the sticky and salty substance. You looked back at him and he was blushing at your actions. During the what had happened your heat had risen again. Sans apparently knew how you felt because he pushed you down onto the bed again. "Now comes the fun part." He said with a lust filled voice. He lifted your legs onto his shoulders, having his member right at your entrance. You looked at him a little worried. "Don't worry. I'll go easy, okay?" You nodded, trusting him. He positioned himself: "It will hurt at first but it will feel good after." You hesitated a little but nodded, it was too late to go back now and you also needed this feeling gone! He gave you a comforting smile, before pushing in. He didn't lie, it did hurt. You were trying to suppress any noises. He was finally fully in, filling you up. Your hands had been clenching the sheets tightly. He waited for you to adjust, whispering sweet things to you and caressing your body, trying to help you. Pleasure was mixing with pain, numbing your mind. Thanks to your heat the pain soon turned into pleasure, dragging a little moan from you. He looked at you: "Can i move?" He asked you with concern. You nodded and smiled at him faintly. He started off slowly, thrusting in and out. Your head emidiatly fell back, along with a lot of moans. "S-so tight!" Sans managed to get out. You were overwhelmed by the pleasure, created by the oh so needed friction. You couldn't speak, every try being interrupted by moans. Yet you wanted to tell him to go faster, that you needed more. You gave him a needy look, along with a whine for more. He got the message and quickened his pace, ramming into you. You threw your hands around his neck, holding onto him for dear life. He had hie hands placed on the bed either side of you, grunting and moaning slightly. You on the other hand were a moaning mess. This feeling, even though new, was heaven. You didn't want to stop. His pace had quickened again, not only encouraging your moans but also returning that familiar pressure again. It was building slowly but surely. Sans was pounding into you by now, hunched over your shaking frame. He pulled you into another deep kiss, muffeling your moans. You gladly kissed back, your limbs still tightly wrapped around his bones. The kiss turned into a heated make out session. You now had a faint idea of what to do, so you tried your best. Of course you were still a little clumsy, this being your first time. After a few seconds he broke the kiss, leaving a string of saliva connecting your lips. Your faces were inches apart while he was pounding into you. His eyes were full of lust but they also held other emotions, love and care. The pressure had increased a great amount, signaling you were close to your limit. His groaning and curses under his breath, showed he was getting close as well. "(Y-y/n-n) i'm getting c-close." Edge managed to get out in between his groans. "M-m-me t-too!" You forced the words out. The pressure was at its limit, close to snapping. Sans gave a few more thrust and a loud moan errupted from him, before you felt a warm liquid enter you. This caused your own release, the knot in your stomach finally snapping, forcing you to give out a screamed moan. Your whole body tensed up, while Sans made a few more thrusts to ride out your orgasms. Not even a second later your body relaxed completely, going limp in Sans' hold. He caught you and pulled out, making sure not to hurt you. You could hear your soul beat and feel your body throb. Your heat had disappeared but now you were extremly exhausted. Sans layed your weak form onto the bed and got in next to you, pulling a blanket over the both of you. "How was that, sweetheart?" He asked in an exhausted yet caring and loving. You on the other hand were way too tired to speak, instead you just cuddled into him. He wrapped his arms around you, keeping you very close to him. He chuckled a little before giving you a sweet kiss. "I love you, (y/n)." You worked up enough energy to reply: "I love you too." But that was all. You felt the land of dreams tug you into your well deserved rest. You fell asleep in the arms of your boyfriend, happy about what had happened.

(I'm done. This took so long. It might be terrible though. It's late at night, i'm extremly tired but i wanted to finish this, for those who wanted a lemon/smut. Here it is! This is my first ever lemon so i hope i did ok. Anyway let me know if should release my other books. Till then. Good night! I'm litteraly about to die out of tiredness!)