After agreeing to help Gaster with an experiment, you wind up in his laboratory naked and spread out on an exam table. Tentacles lazily wrap around your body and the thickest appendage, bigger than all the others, rubs against you, slicking you up. "Alright, I’m ready,” you say nervously, cheeks burning.
Gaster rubs your leg in a comforting gesture. [DON’T FRET. IF YOU WANT ME TO STOP, I WILL. JUST SAY THE WORD.] He chuckles. [I WANT THIS TO FEEL GOOD FOR YOU. I’M SO OVERJOYED THAT YOU’RE PARTICIPATING, I CAN’T WAIT TO BE INSIDE OF YOU AGAIN.]
You feel yourself flush even more as he praises you, and you squirm on the table. “Yeah, I can’t wait too,” you say truthfully. “Last time felt amazing.”
Gaster hums at your response and the tentacle throbs against your body. A moment passes and it finally penetrates you slowly, filling you with ooze as it burrows inside. You feel it pulse and expand inside of you and when you look back up, you see a small bulge moving through the tendril. Soon, you feel something hard being pushed into you, and you whimper as you tighten up when it fully slides inside. Another egg slithers down the tentacle, squeezing into you with a squelch. You clench again, impulsively, but the tentacle opens you up again and deposits more ooze inside.
[IS THIS ALRIGHT?] Gaster asks, gently patting your stomach, admiring the small bump that’s already started to develop. [YOU’RE DOING SPECTACULARLY. YOU’RE THE BEST ASSISTANT.]
His words give you a momentary morale boost but you yelp as another egg is laid, and then another right after it. Slime seeps out of your entrance. You notice that your belly is starting to show the effects of the brood inside of you. A particularly large mass shoots toward you and you can’t help but cry out loudly as it presses against you. The tentacle pumps you full of ooze, attempting to get the egg inside. “Gaster, i-it’s too big!” you whine. “It’s not going to fit!”
As you squeeze your eyes shut, you feel the tentacles forcefully shift your position and lift your legs higher, giving the biggest tentacle better leverage. It surges and stretches and the egg finally enters you with a plop. A gush of liquid follows it, and another egg slips past your opening. You vaguely wonder how many eggs Gaster intends on filling you with.
The tentacle shows no sign of stopping soon, and it keeps pumping egg after egg into your swollen body. By now, you feel incredibly full, and your stomach is stretched out more than you’ve ever experienced before. You’ve lost track of time and you feel completely exhausted.
Gaster’s voice brings you out of your haze. [JUST ONE MORE EGG, AND THEN YOU’RE DONE.] he states, clasping his hands together. You can see that the last egg shooting down the tentacle is much larger than any of the others. You whimper as it makes contact, but it slides in easier than you thought. You wonder how stretched out you are. A final slurry of fluids enters you, and you feel the tentacle pull out. You immediately clench up, but a wave of ooze drips onto the table and floor. You try to steady your breathing.
The tentacles unwrap from your body and Gaster steps forward, dwarfing your body. His grin is the largest you’ve seen so far. [THAT WAS TRULY AMAZING. YOU DID SO WELL, HUMAN.] he exclaims. He leans down and nuzzles your body. You let out a breathy moan.
[BUT, I’M NOT DONE YET.] he says eagerly, running his hands across your bloated stomach. [I WANT TO DO SOMETHING FOR YOU SINCE YOU PERFORMED SO PERFECTLY.] Before you know what’s happening, Gaster wraps his arms around you, gently scooping you up. [THOUGH, SOMEWHERE ELSE, LESS CLINICAL.] You feel the eggs jostle in your belly as he hoists you off the table. Vaguely, you can see one of his phantom hands grabbing a cup of something on the way out.
YOU ARE READING
lol goopy smut
Romance💀I did not originally write this, it's just a story I found that I rlly liked, 💀 it's a lemon fic of reader x goopy gaster, this contains adult themes such as breeding, so minors beware! I might make more than 1 chapter, so eh ( made in 2022)
