Their body quaked softly, rhythmically. Thighs spread wide apart, yet so bloated that they may as well have been pressed together, they bucked their hips in time with the toy that pumped steadily inside them.
Touching themselves had become too difficult of late. Their arms struggled to reach past the hill of a gut that jutted out in front of them. Grinding against their pillow? Exhausting. Using their imagination simply wasn't enough to get them off. So it was with a sense of frustration and desperation that they finally caved and ordered the thrusting toy from a somewhat sketchy website. Their horny, porn-rotted brain barely registered anything on the site beyond "HANDS-FREE ORGASM" and "BIGGER PLEASURES". That was enough for them to buy it.
Setting it up, they struggled to read the garbled text on the instructions. "ENGAGE BUTTON FOR LIPID INJECTOR" made no sense to them and at this point they were too pent-up to think too hard about it. Positioning it between their ample, shaking legs, they turned it on. It slid slowly inside them, filling them, making them gasp softly and fall back onto their bed, then slid back out.
Immediately hungry for more, they grabbed the remote that came with it, turning up the speed. The toy picked up the pace instantly, the pneumatic whir of its internal workings growing louder. Throwing their head back, moaning, they felt their entire body jiggle and quiver. This toy had some impact to it! Caressing their swollen belly, they gave in to the thrusting.
It wasn't long before they came, the incessant pumping drawing out an intense, prolonged orgasm. Panting, sweating, their breath ragged and heavy, they sat up, watching the toy continue thrusting into them. Gripping the remote tightly in their hand, they squashed the buttons randomly in their doughy palm.
A warm, thick sensation suddenly shot inside them, making them fall back onto their pillows. The pump-pump-pump of the toy became almost unbearably intense, and they suddenly felt too heavy to move away from it. In horror, they could see their belly rising, expanding suddenly. The same was happening to their limbs, an unstoppable, fatty bloat that increased with each deep, hard thrust.
Their mind scrambling, panicking, they then realised what "LIPID INJECTOR" might mean. This toy was pumping them with fat! The aggressive pounding inside of them, forcing fatty fluids into their body, making each inch of flesh swell, was almost too much to even comprehend. Panting harder, sweat dripping from their pores, they attempted again to pull away, but with no luck. Their body had become too heavy to move. They could only lay there, moaning, cumming and expanding. Their double chin quadrupled, burying their neck, bouncing in rhythm with the toys ceaseless thrusts. No longer could they see past their engorged breasts and now mountainous belly. Their arms and legs, ballooning in size, kept them pinned in place, spread wide as this machine kept its pace, unfeeling, unthinking, only doing as its programming commanded.
The last thing they could remember seeing, before passing out, was the instruction leaflet beside them, with the words, "NO REFUNDS, FATTY" written on it.