Pulling My Heartstrings (Undertale Au Smut)

Nightmare x Top!Reader

"Boss?" I walked into Nightmares office, looking around a little. I didn't see him the moment I walked into the room, but I suddenly heard the door close behind me as I walked deeper into the room.

"H-Hey Y/n" I turned around and saw nightmare; rather surprised he was in his passive form. He seemed really flustered and I was taken a little off guard as he walked over and hugged me. "I uhm.. have a little bit of an issue right now I need you help with.." He trailed off as he looked down at the floor, a purple blush growing on his cheeks.

I sighed and shook my head. It wasn't unusual for Nightmare to be like this when he was turned on, which was rare in itself, but I was still surprised. It was only natural though.

I gave him a small smile, wrapping my arms around his neck and pulling him closer, his body pressed against mine. His eye widened and he looked up at me, his face blushing a darker shade of purple.

I leaned forward and gently kissed his forehead, smiling and leaning in close, whispering to him. "I'll help you~"

I felt him shiver and watched as his eye closed and his body relax. He took a deep breath, trying to calm himself, before speaking.

"I want you to tie me up and do whatever you want with me."

My eyes widened slightly, but I quickly regained my composure. I smiled, pulling him in and kissing him again, this time on the cheek.

"Alright then. I'll take care of you."

Nightmare nodded, stepping back and letting me get to work.

I went over to his desk and grabbed some rope that was in the same place as last time he'd done it to me. He followed behind me, and I could see the excitement and nervousness in his eyes.

I tied him up and placed him on the desk, his hands above his head.

He was so cute like this. His face was flushed a bright purple and his breathing was heavy. I smirked and started removing his pants, exposing his bare legs and thighs. He was already dripping with precum, his cock throbbing.

I began to stroke his cock, and he gasped and arched his back. I could feel his whole body tremble under me as he whimpered and moaned.

I leaned down and kissed his neck, running my tongue along his sensitive bones. He whimpered and squirmed under my touch, trying to free his hands, but the ropes held tight.

"Mmnnn... please..."

I moved down his body, kissing and licking along the way, until I reached his member. He moaned as I licked the tip, and I took his cock into my mouth, sucking gently.

"A-Ahh..." He moaned, arching his back and bucking his hips.

I sucked him harder, and he moaned louder, thrusting into my mouth. I gripped his hips, keeping him still as I took his full length into my mouth, moaning.

"D-don't stop..."

He thrusted his hips up and down, and I began to bob my head, swirling my tongue around his member.

"Nngghh... ah! Fuck..." He threw his head back, his eye wide as he came, his seed spilling out into my mouth. I swallowed every last drop, licking my lips.

I stripped out of my clothes and climbed in top of the desk, straddling him, "Yknow love.. You really always help you relieve your stress when you need me to~ I can even stay here in your office and do things with you, just let me know and I will~" I smiled down at him, grinding myself on his length.

He let out a groan and his hands clenched into fists.

"I k-know.. P-please..."

I nodded, taking hold of his member and slowly lowering myself onto him. I felt his cock twitch and throb inside me, and I moaned as he filled me up.

He panted and writhed beneath me, trying to thrust his hips, but I held him down, gripping his shoulders.

"Nnghh..."

I started riding him, bouncing up and down on his shaft, moaning as his cock rubbed against my walls.

"Oh god..." He moaned, his eyes fluttering closed.

I rode him faster, and he cried out in pleasure, his cock pulsing inside me.

"Yes..!" He groaned, his hands clawing at the air.

"Fuck yes..."

I fucked him harder, and he screamed in ecstasy, his cock throbbing inside me.

"Mmnnhh.. Ahhh... Fuck!" He came inside me, his cock throbbing.

I moaned, cumming all over him, and panting.

I smiled and kissed his forehead, "You know.. next time I wouldn't mind topping again-"

"Good luck with that one Y/n" He smiled a little, regaining his composure a bit.

I chuckled, "It would be fun, but we can discuss it more later~"

"I suppose"