Matt wasted no time trotting out of the barn. With the farmer paying him little mind and the farmhand absent, this could be the break he needed. He sniffed the air, pulling back his black, rubbery lips and flaring his wide nostrils. He didn't detect any scent of the jenny, but did that matter? She'd hardly been proven uncooperative.
He could do this without her. He'd been waiting for three days now, those big, black wobbly balls churning, only to be denied release time and again. He'd woke already feeling horny, the black hose of a cock snaking its way out of his sheath, first for a quick piss, and now eager to bring him about a satisfactory explosion.
He just needed something to push against or rub against. But what?
Matt turned a corner, trotting behind the barn, into an area down near where the farmer kept some pigs in a sty. Perhaps because the smell was already horrendous in that area, thanks to the pigs, the farmer had also built up a huge compost pile. The large mound of rotting organic matter festered under the sun. Swarms of dark flies buzzed over the mound. Some of them flew through the air and began to buzz around Matt's snout and ears as he approached the mound.
He needed to act quickly before the infernal device did something to thwart him. The stomach-turning scene revolted his human sensibilities, but his aching cock stretched and bobbed under his sagging belly. Treating the mound much like a jenny, he reared on his back legs and surged forward, sliding his hard cock into the oozing mess. The warm, damp mound proved perfect. He slid his cock in and out of the rotten softness, braying in his eager excitement. From the nearby sty, the squeals of hogs responded.
"Oh fuck," Matt brayed. "It's so disgusting..."
Shreds of rotten vegetation clung to his furry belly. Oozing stains soaked into his fur.
"Let me cum!" Matt brayed. He almost expected the hand to appear and interrupt him at the critical juncture.
He released a truly beastly bray as his whole body shook as he expelled the contents of his full balls to add one more organic, bio-degradable substance into the compost heap.
His mind almost blank with pleasure, he continued to hump the mound of insensate and mouldering vegetable matter.
Slowly, as he withdrew his spent cock out of the greasy ooze, he realized nothing had changed.
"Why?" He brayed as some thick donkey cum still dribbled out of his cock.
He should have swapped back already. He should be back inside his body, not still trapped as a stupid ass.
Matt's huge but excellent ears heard the crunch of the tires of a truck hauling a trailer swing into the barnyard.
Matt trotted into the barnyard at the same time the farmer emerged from the barn and the other farmer exited his truck.
"You're back sooner than I expected," the farmer said.
The other man nodded. "Yea. I thought about it. I reckon I'll take that jack off your hands."
The farmer smiled. "Let's get him loaded up then," he said, worried the man could change his mind.
Matt saw the blurred shape of the farmer approach from the side.
"Stop!" Matt brayed. "Wait!"
The farmer grabbed Matt's bridle and gave a tug at the same time his face twisted in disgust. "Phew, what the hell have you gotten into?" The farmed asked, noting the donkey's filthy state and an even more vile stench than usual clinging to the beast's hide.
The two men knew their way around donkeys and soon had Matt secured in the carrier. The jenny and alpha jack had wandered into the barnyard in time to see off their unlamented compatriot.
Matt tugged on his bridle, which had been fastened to a restraint to help steady him for transport.
"Don't!" He tried again to speak. The resulting bray echoed loudly in his head as his heart began to race. Something with the Chronivac had gone badly wrong, and now the farm represented stability for him.
The truck lurched into motion. Through the bars of the carrier Matt watched as the barn, the farmer, and the other two donkeys receded as he was transported away.
He continued to bray, which got one response. The alpha jack produced its own brays, indifferent to the plight of Matt. The alpha wasn't bothered in the least to see the last of Matt's sorry hide.