A hose drops from ceiling, attaches to muzzle, forces way down the subject's throat and starts streaming hot milk directly into his belly. The subject would start to feel full, then overly full, then bloated as the body starts to absorb the milk almost as fast as it's being pumped into his stomach, his toned body slowly softening as a layer of fat grows, widening and sloshing as the milk continues to fill his stomach.

A strange pressure would start to grow in his belly, the skin feeling strange even amongst his fatting form, but before he could be able to look down some sort restrains grab his arms and legs, jerking him into a horizontal position as the sloshing milk inside his form slams against his prostate. The subject would moan into the hose, the sloshing of the milk jamming repeatedly like a good fuck, soon joined by the feeling of hot warm liquid being spurted onto his butt and a second hose jamming its way inside.

Looking several hundred pounds of fat heavier, the bloated subject would moan as the strange feelings in his stomach swells further, feeling similar to his bladder after drinking a cup of water, then a second, then four, then feeling like he's been drinking a few gallons without a chance to visit the bathroom - but it's not his actual bladder, as he eventually notices from a mirrored surface, but an udder growing and swelling, four long and erect teats already dripping with milk. The hoses in his mouth and rump slow the flow of dairy to an eventual stop as the milk starts to drip from the subject's udder onto the floor, leaving him hanging there with the pressure of the milk in his round form and the sloshing of his overfilled udder underneath him.

A whirring sound can be heard and something like cotton candy starts rushing into his muzzle and butt, seeming to fill him tighter and tauter. A strange tingling and a... softening sensation spreads out from his throat and colon as the fluff begins to convert his insides to other fluff, bones, muscles, and organs dissolving into thick cotton wadding. The skin around his throat and swollen middle would start to turn into a silk-like fabric, the fur of his body becoming thick soft bristles of faux fur, and a high quality one at that. Eventually it covers his entire body, his eyes becoming harder to move and even blink as they eventually widen and harden, turning into glass ovals. The hose from his muzzle extracts itself just as the fabric of his lips sews themselves together, sealing it shut as the wadding fills his head and body, the former rolls of fat-infused skin now round, with some give but solid shapes.

The only thing left of his body was his udder, still straining and full, and what felt like his prostate that had been moved directly against it, the movements of his milk-filled sack rubbing against it and filling his mind with pleasure. The flow of fluff from the tube in his but stopped as he felt something big and plastic enter him instead, being placed inside his belly. He feels a slight click as it connects to his udder, which is rapidly becoming stiffer as the flesh there turns to rubber, a soft squeaking sound sways and forth. A feeling of unfolding as his overfill sack spreads to his entire body cavity, with his anus magically becoming a whole piece of fabric as the hose slides itself out.

The momentary silence is broken by the sound of a suction hose as four tubes attach itself to his now rubber udder, the subject moaning as they milk him, the feeling washing over him like a combination of the best orgasm and relieving the pressure of his bladder, letting out a slight whine of discontent as they finally drain his udder. A  feeling builds in his middle as a strange warmth grows, and the feeling of his udder re-inflating with more milk washes over him, building higher and higher, squeaking as it stretches, until he feels something inside him give, and the milk his udder generates starts flowing inot his middle, the overflow sack starting to properly inflate with the hot liquids, pressing harder and harder against what was now his prostate, his belly and middle swelling and shoving the cotton wadding into the subject's limbs, bloating and stiffening them to the point of immobility. The bladder continues to fill, mixing the strange feeling of being overfull with the continue pleasure from the pressure on his prostate, the fabric of his skin giving up what slack it had to become full, then tight, the seams of his joints and head starting to strain as the growing udderplush mentally screams in pleasure, begging for release.