Making Sense of Things
He doesn't know when he started; Jim doesn't even know the first time he noticed. But by now he knows that every so often he'll catch himself doing it.
No doubt it's a perfectly reasonable thing. Blair would have, or quickly formulate, a theory for it; it's exactly the sort of thing he'd love to know. More data for the thesis -- more information to pump through his brain.
Sometimes Jim thinks that information is the oil that keeps Blair's brain cells primed. Other people's brains need oxygen and glucose. Blair's brain requires new -- constant -- input or he'll stop moving like a rusted tinman, trapped until someone whispers something academically intriguing in his ear.
Jim doesn't tell Blair these things. He's fairly sure Blair will simply laugh at the second one, then agree with it. But he'll be likely to ask what brought the thought on and Jim knows he doesn't want to explain it. It's bad enough that he does it. It's always subconscious -- maybe even unconscious sometimes, because obviously he has no idea how often he does it without realising it at all.
It's perfectly normal, Blair tells him, for a Sentinel to track his Guide. That part they both know, and that part Jim has finally got used to. Keeping track of where his Guide is -- ironic as it sounds -- normal. most of the time he does it without conscious intention. It's only when people start shooting or Blair says "trust me" that Jim does it deliberately. Hearing Blair's heartbeat or tracking his scent are just parts of Jim's usual routine.
What he doesn't understand is why sometimes that isn't enough, and he discovers that he has wrapped himself in Blair with every sense he can.