Tears streamed down Bobby's eyes while Master Dave, his owner, caressed him in his strong arms.
"There there", the wolf said, whispering in the young rat's ear, "it'll be over soon".
Master Dave gently moved his paws over Bobby's thighs, making him shiver, with pleasure from the sensation, or with fear for what was about to happen, Dave didn't know, and frankly, didn't really care. After all, Bobby wasn't here to enjoy himself, no far from it.
The boy's hands had been tied behind his back, and he instinctively reached for his owner's sheath, as he had been trained to do since birth; he had known no other life and knew this day would come, he was raised for this, but that didn't make it easier.
The wolf slowly started humping Bobby's tied up hands, while his own hands moved up to the rat's exposed little cock.
It was the first time it had been removed from its chastity cage, and the rat didn't really know how to respond to it, the stimulation of his cock was new to him, the exquisite feeling almost made him forget what was going to happen today.
Master Dave moved his cock away from the slave's hands and placed it at the boy's pink hole, below the equally pink, hairless rat tail. Stretched from a lifetime of poundings, he slipped in quite easily.
Bobby gasped slightly, he was used to getting fucked, but the combination of getting masturbated while having a cock inside him made the whole experience new to him.
The wolf continued stroking Bobby's cock, and felt the boy's ass clench around his cock as the boy had his first (and last) real orgasm of his young life.
At that time, Dave pushed his knot into the tightened hole, but it didn't hurt Bobby, he was experiencing an ecstasy he had never felt before, lost in the moment of pure joy.
Dave had seen it several times, with the boy's predecessors. Bobby was ready.

The wolf came moments after his slave, filling him up with his seed and let him rest on his lap for a few minutes, before pulling out, and putting him on his feet.
He removed the last remaining inorganic pieces from the rat: the small nipple piercings, the collar, and finally, even the bounds keeping the slave's arms together. 
Bobby starting shivering as Master Dave kissed his neck and cheek.
"Can't, can't I stay a little longer?" The boy finally asked. He had been silent all day, after realising his time was up. 
"No my little angel", Dave replied, "you knew this was what you were raised for".
He had had a wet dream last night, a small mess around his chastity cage, visible for master to see, as he slept each night with his hands and feet bound to the corners of the bed.
Bobby had never felt uncomfortable, because he had never known any better, but seeing the the small pool of cum that morning, made him try to get loose for the first time, cause he knew what it meant.

For a slight moment, Dave felt regret about what he was about to do. The rat had always been such a good boy, and his mouth had serviced his cock like no other rat before.
But there would be others after him, many others, as there had been many before, this was no different.
"Here, this'll make it easier".
Dave injected the boy with a small serum, which would render him immobile, but not unconscious, nor numb.
"Well, not easier, just quicker".
The rat was completely limb, except for the tears still welling up in his eyes, as Dave carried him over to the terrarium, giving him a final kiss, before tossing him in.
"Goodbye".

The large boa constrictor knew the routine and went for his prey quickly.
Paralysed and unable to flee, Bobby felt the adrenaline rise in his stomach. He knew this day would come, but he wasn't prepared to die.
He wanted to call out to his owner, who he loved, but was now watching with an expression he had never really seen, hunger, lust.
Master would enjoy seeing him get eaten, that at least was good thought to hang on to, while the snaked started wrapping itself around the boy's tiny body.
He wanted to scream as a rib cracked under the pressure, but even if he hadn't been paralysed, he wouldn't have been able to, as the boa was now squeezing around his throat, cutting off his air.
"At least it'll be over quickly", Bobby thought, as he went unconscious, the life fading from his teen body.

Dave looked on, still surprised how the snake could devour something much wider than itself.
He started stroking himself, and despite having cum not that long ago, felt another orgasm building up, as the last of the rat's body disappeared into his pet snake's mouth.
He was quick to catch his seed in a small bottle, before walking to the infirmary next door, where he picked up a newborn rat.
Taking the infant in his arms, he walked back to his pet's terrarium. While he bottlefed the boy his cum, he pointed at the boa, who was now resting while digesting Bobby.
"Look, once you reach puberty, he will eat you, but before that, we're gonna have a lot of fun. Now let's find you a chastity cage for that little baby dick of yours"
Dave kissed the newborn on his cheek and gently moved a claw over one of his nipples, oblivious to the life of servitude ahead of him, and the painful end in several years' time.