Gaara is curious. R for vague... 'self-exploration.' Ahem.
When Yashamaru spoke of love, Gaara was sure he was seeing it, somehow-just a little falling out from behind eyes that were just like his mothers; eyes that he never saw, and eyes that would have looked at him the way Yashamaru does, softly and kindly.
Yashamaru dying, and saying those things-all of those terrible things that hurt Gaara the only place he could be hurt-that stripped the definition bare again. Gaara, later, figured that Yashmaru's love was for his mother; that love can take different forms for different people.
He fought Rock Lee, and his busybody teacher; Gai-sensei, and his strength of heart-his sheer insurmountablity-that was a solid, mountainous kind of love that was never overlooked or taken for granted. It was the heroic kind of love. Gaara saw this and had begun to understand.
It took Naruto, in the end, literally beating the knowledge into him. After that-the reaching out, the kind of love Naruto had for the world and for Gaara, because they were th same on the inside-after that, Gaara was, at the very least, acquainted with love.
It was Naruto saving him, Naruto bringing him back from the dead, Naruto fighting through Akatsuki, which was just as bad as Hell itself, and then smiling down at him with his broken-joy smile-that brought him to close quarters with love. That was when he started to fully understand it.
Usually, the love of the spirit takes the longest to comprehend, to develop the fluency required to really slip inside another person and connect with them; Gaara developed this first.
And it was because of this that the general reaction to spiritual love-physical love, and slight changes that the body implements-were completely lost on Gaara.
It started with a thought, because Gaara thinks of Naruto often. He usually doesn't have so much time, because he is the Kazekage and he is quite busy; and now that he sleeps, he has dreaming to get used to.
The thoughts lead into dreams. They are strange things, and he sometimes has trouble just relaxing in his own head without the menace of Shukaku lurking in the corners.
He dreams about Naruto, and a warm settled around his heart. It is comforting, and sinks, warming his ribs and his stomach until he's full of the golden heat that Naruto instills in him-it is kindness, it is connection; it is love, Gaara knows.
But it does not end there, and the comfort thickens, coils in his gut and something twitches somewhere and-Gaara wakes up.
There is a throbbing, an aching; it is unbearable. He slides a hand down to inspect, considering; how could he have hurt himself sleeping?
His fingers slide around the area of note, and they tighten curiously. This is new.
There is a slight wetness on the tip, but no blood; he is not injured. He squeezes, just a little, and gasps; this is definitely new.
He fumbles for awhile; while his hands are soft and gentle, he is largely inexperienced and it takes him a while to work out the motions, to decide what feels the best, how to shift his palm, how to close his fingers in, how to...
And then it happens. He makes a small noise he's never made before, even in the heat of battle, and it's largely from surprise than anything else-though the sensation is novel and very, very Good.
And then there is a mess, and Gaara is frowning-he doesn't like surprises too much, doesn't like new things, even if this was good. He wonders if he should ask his brother about it in the morning; his brother would know about these things.
Gaara does not wait until morning; he slips out of bed and pulls his robe on.
On the other side of the compound, Kankurou wakes up in a cold sweat; he's had a nightmare, he's sure, but he can't remember it.
When there's a knock at his door, he almost has a heart attack; when his little brother enters, it's a milder one, and his blood pressure is almost back to normal by the time the demon-haired boy takes a seat on the side of the bed.
It skyrockets again, however, as soon as Gaara asks,
"Which kind of love is it that makes it har..."
He doesn't hear anything after he passes out.