Pulling My Heartstrings (Undertale Au Smut)

Blueberror x Reader

"Blue..?" I called out for my partner softly as I walked through the house, we had recently found him left in the void and he'd turned rather... glitchy, I guess. I approached his room quietly and peered inside, squeaking as I was suddenly pulled inside and pinned against the door to close it. Blue was a little shaky, and his bones were dark shades of purple, blue, and mostly black with yellow star markings on random places.

He seemed distraught and I frowned, "B-blue... What's wrong-"

"Are you scared of me?" He quickly asked, "D-do you still love me even though I'm different?"

"..Of course I do Blue..." I sighed, hugging him as he held me to the door.

We stood there in silence for a long time before Blue started to cry, causing me to panic a little.

"W-whoa-hey! It's okay, I-I promise I still love you no matter what! Y-you don't need to worry about being scary or anything-"

"But I'm not the same..!" He whimpered, "You're just saying that, I know it."

I sighed, hugging him close, "You're still my Blueberry, that's all that matters."

"...Really?"

"Yes, really, you nerd," I teased, earning a soft smile and chuckle from the monster.

I smiled, looking up at him, "See? I love you no matter what.."

Blue smiled weakly, leaning in to kiss me. I closed my eyes and kissed him back, squeaking softly when his hands started to move. One went to my lower back and the other cupped one of my ass cheeks, pulling me closer.

I felt something warm and wet slide across my bottom lip, making me shiver as I opened my mouth. My breath caught in my throat as his tongue tangled with mine, he was a good kisser... I never knew that.

He pressed me into the door harder, his hands trailing to the hem of my shirt and under it, making me squeak and my breath grow uneven as his cold hands moved over my ribs and up to my breasts.

I could feel his magic forming and it made me nervous. I had never really... Done this with anyone before. Blue seemed to sense my hesitation and he pulled back, panting softly.

"Do you want to stop..?" He asked softly, "I-I won't mind if you don't want to..."

I gulped and shook my head, "No-I'm just nervous... I've never done this before.."

"O-oh..." Blue stuttered, blushing, "M-me neither.."

I gave a small smile and blushed, "W-we could, um, f-figure it out t-together?"

He smiled softly and nodded, leaning down to kiss me again. I relaxed and kissed him back, my body warming up from the contact and the blush on my face growing brighter.

His hands went back under my shirt, slowly rubbing over my breasts and stomach before trailing down to the waistband of my pants. He hesitated and looked to me, as if asking permission, and I gave a small nod.

He then slowly pulled off my pants and underwear, making me squirm and try to hide my lower body from him. He gave a small chuckle and held my wrists gently, kissing me and pressing me back into the door.

I blushed brightly and shivered as his hand slipped between my thighs, his finger rubbing my clit gently. My breathing hitched and I gasped as his teeth moved down to nip and kiss my neck.

I was getting wetter as he kept playing with my clit and rubbing his fingers around my entrance, teasingly slipping a finger inside me before pulling it back out.

My legs shook as my arousal grew, moaning softly and gasping every time his fingers pressed and rubbed over the sensitive spot.
"A-ah~.." I gasped and whined as he slipped two fingers inside me, making me shiver and squirm, "B-blue.."

He kissed me passionately, his tongue tangling with mine as he started to pump his fingers in and out of me, making my legs shake and my breath catch in my throat.

He then slipped another finger in and I broke the kiss, throwing my head back against the door as I panted and moaned, "A-a-ah! Blue~"
He was now rubbing his fingers over the sensitive spot again, making me gasp and cry out.

"B-blue~!"

He continued to finger me, his fingers curling and thrusting, rubbing my g-spot until I came hard. My body shook and my vision went white, my orgasm making me cry out and moan.

When I came down from my high, I was panting and Blue was holding me against him as he carried me to his bed. He gently set me down on the soft mattress, making me blush as I saw him lick his fingers.

I gulped and blushed more as I watched him remove his clothes and I got to see his erect cock. He was bigger than I had expected, making me even more nervous.

"Are you sure you want to do this?" He asked me softly, looking me in the eye, "I won't be mad if you want to stop."

I nodded, "y-yes.."

He smiled and climbed onto the bed, pulling me closer to him as he did so. His body was warm against mine and I shivered, my body heating up.

He then leaned down and kissed me, his hand sliding down between my thighs again. I whimpered softly as his fingers rubbed over my clit and rubbed his length against me, making me gasp and arch.

"B-blue.."

He groaned in response, kissing and sucking on my neck as he pressed his cock against me and slowly started to push it in. I moaned and shivered as he entered me, his cock stretching me out as he filled me.

When he was all the way in, he stopped moving, waiting for me to get used to his size. When I nodded, he slowly started to pull out and thrust back in, making me moan.

I felt his teeth nip at my neck, leaving a small trail of bite marks and hickies. He then started to speed up his pace, going a little deeper and harder each time.

"Ah-~ Blue~" I moaned out, gasping and crying out as he went faster, "B-blue~ Oh god-A-ah!~"

He kissed me passionately, his hand finding my clit again and rubbing it as he thrust into me, sending jolts of pleasure through me.

I arched and moaned, panting and moaning his name as he thrust harder, his fingers rubbing and circling my clit faster. I could feel myself reaching my end, getting closer and closer until I came, my walls squeezing around his cock and causing him to groan and thrust harder, cumming deep inside me.

I moaned loudly as he came, my body shaking and twitching as he filled me with his seed.
We both panted, his hand gently petting my head, making me hum happily.

"That was.." I started, but Blue chuckled, nuzzling into my neck and smiling.

"You were amazing, love." He whispered, "Thank you."

"You're welcome, but.. Why did you thank me?" I asked, confused, "I didn't really do anything.."

He shook his head, "I should be thanking you for staying with me even after I changed.. Even though I'm like this now, you stayed.."

"Blue.." I sighed, nuzzling him, "I'm not afraid of you, I never was. You're still the same sweet and caring monster I fell in love with."

"Y-you mean it?" He asked, making me nod and smile.

"Of course."

He smiled and nuzzled me, sighing happily. We cuddled and talked for a while before I fell asleep, his arms holding me close.