You think about what kind of dog to become, and narrow it down to either another Rufus, or like your neighbor's German Shepard. After a few moments of thought, you decide to...
Become Rufus
Being Rufus seems like the best option, that way you can really see what it's like to be your best furred friend. He's a good handsome dog too, and that might be something you'd like to feel too
You tell Rufus to come, and he follows you to the back door where you let him outside and go out behind him. You shut the door behind you so neither of you go inside and mess something up. Turning back to the yard, you see Rufus walking around sniffing the fence as usual. You take a deep breath and check for anyone who may be watching. You see no one, but just to be safe to walk over to a bush beside the fence and hide behind it
You take a breath, and start to concentrate. You want to be Rufus. You think about his canine figure and his luscious golden fur. You think about his floppy ears, his snout, and of course his tail. You imagine your face stretching into a muzzle, and can almost feel it happening while you think about it. You imagine your ears flopping over and becoming dog-like, and again you can almost feel it happening. You take a few minutes to think about all the parts that need to change, not really knowing if you need to concentrate so much or not but doing it anyway
You open your eyes to find yourself standing only two and a half feet off the ground. You immediately notice the furry muzzle sticking out from your face as it obstructs a part of your vision, and can't help but smile a big doggy smile. It worked! You turn your head around and see the rest of your new canine body. You laugh, or would have if you could, as you see and feel your new tail wagging excitedly. This was so darn cool! You could pull off so many things with this! You can't help but bark a couple times in excitement, which brings the real Rufus rushing over to greet the loud newcomer... you
"How'd you get in here? The walls are too high to jump and I don't see a hole under it." Rufus barks at you, but you somehow understand him. Shocked, you just stare at him for a moment, your tail shot up and sticking out in surprise. He comes a little closer and starts to sniff you
"Wait... you're... but you can't be... where'd you come from?" He sounds very confused, and you suppose he would be, knowing you're a perfect copy of Rufus himself. You start to respond and can't get over the fact that you are talking to your dog!
"Rufus, it's actually me, Marcus! The guy that takes care of you?" You don't know if he would know your name so you come up with something more specific. "I just brought you outside a second ago, remember?"
Rufus just looks at you, confused. "Marcus? That's a strange name." He walks around you and continues to sniff. "How come you look and smell just like me then? You're not a human, you're a dog!"
"I know, I know! I can turn into a dog whenever I want now! Isn't this amazing? I thought maybe we could play together since I'm here alone except for you. I thought it'd be better to play with you like this!"
"Hmm...." He stops and stares into your eyes for a moment, panting. "I don't know if you're telling the truth, but we can play regardless of who you are, as long as you're friendly." He give you a big doggy grin, one you hadn't recognized while you were human. Maybe a new bit of doggy instincts found their way into your mind while you changed. You aren't complaining though, it's probably why you can understand Rufus and respond so well
"Whatever, can we just play? I have so much energy now!" You get down into a play pose, and Rufus does the same
"Alright alright, let's do it 'Marcus'." He says your name kind of awkwardly and almost mockingly, like a challenge. You take him up on that challenge and lunge for him. He doges quickly and you roll to the floor, popping right back up onto all fours. You chase after him and the two of you begin to chase and play for a long time. You lose track of time but don't really care, you've lost yourself in the fun of being a careless canine with a twin to play with
You chase Rufus around the yard and wrestle with him for ages, until you hear the front door open, and your mom call out for you to feed Rufus. This stops you right in your tracks. What should you do? You can't let her see you like this, but you don't know if you have time to change back before she see's you. You panic, not knowing what to do. Rufus sees your panic and asks what's wrong. You look at him for a second and turn back to the door. You tell him honestly, mostly out of panic, that you have to...