Word Choice to Reflect Character Mood

In the story on which I'm currently working, the main character can possess inanimate objects and make them move around.  He takes it as a point of professional pride that these movements are as lifelike as possible.  His favorite is a paper-craft dog that runs around and acts like a real dog.  The point is that he devotes a large amount of time and effort to making sure people don't know that he's the one moving the dog around, to making it look like he's not a puppeteer, but rather making people believe that the dog is alive and acting of its own volition.

This presents an interesting writing decision.

The emphasis could be on the dog's actions, presented as if it is its own character as most people would see the dog.  "She wagged her tail, the whole back half of her body swinging with her enthusiasm."

Or the emphasis could be on how he is controlling the dog, which makes sense since the story is from his perspective.  "He caused her tail to wag enthusiastically, swinging the whole back half of her body."

So which way to go?  I think it really depends on the situation, and is a line by line decision rather than an umbrella decision that affects each and every instance.

• How much is the main character thinking about his actions?  Is he trying something difficult where he really has to focus on his actions?
• How much has he deluded himself that the dog is a separate entity?
• Is there some fatigue in the paragraph from being specific about that he's controlling the dog.  "Yeah, yeah.  We get it.  He's controlling the dog."  Because it (or at least the example I just used) strikes me as clunky writing and a whole passage written like that is going to slow the story down, but that might be a good device at certain points.  
• How much is he working on deluding others?  Or how plot essential is it at the moment that he's pretending that the dog's a dog?  Reminding the reader that he's controlling the dog would break the illusion.

So basically, it's going to be a continuum, and the choice will reflect the main character's state of mind in the moment.

This is kind of like some previous things I've written where characters use an alias.  Which name I call them depends on who they're with, how they're acting, and if they're identifying more with one personality or another.

I'm sure there are other examples of this.  Any suggestions?