A magic collar turns Billy into Bingo

Billy walks into his apartment and sees something weird sitting on the coffee table: a black leather dog collar with a long chain-link leash. He's confused because he knows his roommate Karim doesn't own a dog and their landlord doesn't allow pets in the building. He'd be pissed if Karim just decided to get one on a whim. In frustration, Billy grabs the collar and examines it.

However, whatever he was upset about melts away as he sees the inside of the collar. On it are various runes and symbols that feel... oddly soothing to look at. It makes him... want to wear it. He undoes the buckle and holds the collar to his neck. Part of his mind wants him to avoid wearing something so demeaning... but the rest of him is screaming with the desire to put it on. To accept an inhuman way of thinking. To feel submissive and lesser to someone else. To give into animalistic urges.

After about a minute of fruitlessly resisting, Billy buckles the leather collar on and lets his identity fall away... sinking deep into his subconscious mind... not gone forever, but completely forgotten until he's uncollared... as his brain is filled up with barks, growls, pants, and whines...

Waking up a few seconds after the clasp was done, Bingo is curious about the tight thing around his neck. He tries to toy with it, but can't do much other than paw at it (unaware that he's curling his human fingers into loose fists). He looks back and forth, not knowing where he was. Then, startled by his knees buckling, Bingo lets out a first confused, “R-ruff,” as he falls onto his hands and knees.

Now standing on his 'paws,' he feels more natural in this pose as he begins to explore the apartment. Bingo starts pawing at doors, trying with little avail to get out of the strange place he’s in. Instinctually, he knows he has to find someone important to him, but he doesn't know how. Additionally, he can't think all that much thanks to the leash threading itself between his asscheeks. The teasing at his hole turns him on to no end, reducing his intellect even further in that moment.

Having to pull himself out of a heat spell, Bingo regains focus and continues searching. None of the ones he first checks are open, and he doesn’t know what a doorknob is or how to use one. Eventually, he finds one of them left ajar, which he can nudge open with his head. Inside, he finds an empty bedroom with a bed in the center.

“Wruff! Ruff Ruff,” Bingo barks, excited by the new environment. He pads over to an ottoman at the foot of the bed and uses it to climb onto the mattress. He pants happily at the thrill of being that high off the ground. The dog wags his non-existent tail, shaking his meaty glutes about in the process. He lets out little grunts each time a cool, metal link in the chain leash swishes against his hole.

Suddenly, Bingo’s attention is drawn to the stopping of a running water-sound he never took notice of. It was coming from a connected bathroom. Then the dog hears a set of wet footsteps padding towards the door to the bathroom… and someone turning the knob and opening said door.

(EDIT: Sorry, accidentally posted before finishing it.)