I used to be human, I'm sure of it.
It started when my wife, as I then knew her, first said that she wanted a dog. I was happy to oblige. I had often played sex games with my mistress, as I now know her to be, and this was another. But if I had known then what it would be like, I would have asked her to do it to me years before.
First she used long strips of soft leather to tie my ankles to my thighs, so that I couldn't stand up, and tie my wrists to my shoulders, so that I could still walk on all fours, and beg when I wanted something. Then she put a tight muzzle around my mouth, so that I couldn't speak, only growl and whimper.
She bought a collar and lead for me, with a name tag. That's when she christened me 'Sparkie'. I forget now what my human name was.
Then she sewed a new skin around my body, made from tough denim so that I didn't hurt myself when I was running around in the garden. It tightly covered my whole body, except for my face, cock and arse. The mittens held my fists clenched, as dogs don't need fingers.
I now usually eat chopped food from a bowl in the kitchen. I'm not allowed to eat in the dining room, but once I've finished eating, my mistress lets me lie in the dining room, curled up around her feet, while she finishes her meal.
Sometimes my mistress's friends come to visit and bring their dogs. I've made friends with a dog called 'Brutus'. I've shown him where I've hidden my secret pile of bones, and if I give him one, he will usually let me rub myself up his hind leg.
I've also met a bitch called 'Beauty', and she lets me mount her. My mistress punishes me badly if she finds out, but she's usually doing the same thing to Beauty's master.
My mistress is very fair with me. Usually I sleep chained up in the garage or kitchen, but if I've been very good, she lets me sleep in her bedroom, curled up at the bottom of her bed. But if I've been bad, I may have to sleep in the garden shed. I usually deserve it, and it teaches me discipline, which is what all good dogs need.
She has put a bowl in the bathroom near the wall, so when I need to piss I can cock my leg. There's a litter tray as well. But sometimes she leaves the door shut, so I have to either bark to get her attention, or go in the garden. And if I ever leave a puddle anywhere, she punishes me.
Of course, on weekdays I have to pretend to be human when I go into the office. But at the weekends I can return to my true, canine form. It's so much easier, living in my true form - no responsibilities, and always looked after by a loving mistress. I'm so glad that I'm really a dog.