Sasori knew full well that Deidara was incapable of grasping the idea of personal space, but often wished the brat could understand the concept of personal belongings.
He'd learned early on about the blonde's little problem. As soon as Deidara had been assigned to be his partner, Sasori had shown him around the base, ending their tour with a stop at their room. Although the puppet master truly detested the idea of having to share a room with his new partner, he really wasn't capable of arguing with Pein about such conditions. Thus, he would have to endure.
Deidara had acted more like a small child than the bomber/terrorist Sasori had been expecting to receive. The blonde stepped into their room and began looking every which way, as if he were a child trying to take in everything all at once. He'd clearly already forgotten his redheaded partner, and began muttering to himself about the new living conditions.
Rather miffed at being ignored, Sasori cleared his throat and redirected the teen's attention to him. "This dresser is mine. The closet nearest to the door is also mine. I sleep on the left side of our bed. My puppets and workbench are off-limits. The rest of the room is yours." Boundaries set, Sasori was positive that they wouldn't have too many problems. Tragically, he assumed that the blonde would actually respect these limits. The Akasuna was quite mistaken.
The first rule to be broken was the mattress border. Deidara sprawled out all over the bed when he slept; as such, he nearly always had an arm or leg (sometimes both) reaching out across the flannel plains of the bed to touch Sasori. Then, when winter came, Deidara would cross the line to try and rob body heat from his partner. Finally, it became quite apparent that if Deidara even remembered hearing Sasori's lecture on who slept on which side of the bed, he either didn't think the puppet master was being serious, or chose to completely disregard the Akasuna's orders.
Next to fly out the window was the rule about Sasori's workspace. The blonde didn't touch the puppets or workbench, per say; that would have resulted in an immediate and painful death. No, Deidara would merely gather up his art supplies and sit on the floor mere inches from Sasori when he was at work, and stay there for hours. Sasori, despite being annoyed at the blonde's close proximity, could do nothing about it. The bomber wasn't disturbing any of his items, and worked silently on his own art, rarely if ever bothering his danna. Scolding Deidara, when all he did was sit at the Akasuna's feet like an obedient puppy, was out of the question.
The dresser and closet rule had to go then, of course. Deidara didn't exactly break that rule in the way you'd think, though. Sasori would have destroyed any and all possessions that the bomber may have hoarded in the puppeteer's storage areas, that was without question. Even Deidara seemed to realize this. So, he went about his mischief in other ways.
Deidara enjoyed robbing the Akasuna of his own clothing.
It had started out small enough; the room had been chilly, and the blonde had wrapped himself up in Sasori's cloak. The puppet master had frowned and muttered a curt, "That's mine."
"I know, un. But danna, I'm so cold, and your cloak's so warm, un!" Sasori had rolled his eyes and dropped the matter.
Later on, the blonde became bolder and bolder, stealing shirts to sleep in and trousers to lounge about in. Sasori would always say, "That's mine," the blonde would always have an argument, and ten times out of ten, Deidara would emerge both victorious and clothed in Sasori's outfits.
Gradually, Sasori grew used to his rules being broken.
After a few weeks, he adjusted to the nights where Deidara would crawl over to his side of the mattress. A few months, and he became used to the blonde creating art at his feet. By the time they'd been partners for half a year, the appearanceof Deidara in Sasori's clothing was such a common sight to the puppet master that he no longer thought anything of it.
That was when he realized that he had a problem.
Solo missions that resulted in him sleeping in empty beds left him longing for the blonde's presence. During the hours wherein Deidara trained outside, kept company with other Akatsuki members, or left their room for any reason whatsoever, Sasori found himself unable to concentrate on mixing poisons or tweaking puppets without the little bomber at his feet. The most drastic and noticeable issue arose when Sasori hanged his clothing up in the closet and paused to think of how cute his partner looked when wearing a few of the shirts.
Slowly but surely, the puppet master was beginning to realize that Deidara had not merely wormed his way into the Akasuna's private living sphere; he was becoming an integral part of it.
After his epiphany, it only took Sasori a few more days to forge an actual relationship between him and the blonde. Deidara accepted his danna's feelings, and adapted quickly to the change from partners to lovers. Where there had once been limits on where the blonde could sleep, now Sasori literally welcomed him to the other side of their bed with open arms. Dating gave Deidara enough leeway to rest his head against the Akasuna's legs when he was at work, and earn a gentle caress for his affections. Best of all, though, now instead of watching Sasori admire him in the Akasuna's clothing, Deidara had the privilege of being admired and undressed by Sasori.
But it wasn't enough. It just was not enough for Sasori. Something was missing.
And so it came to pass that one night, as they lay in bed, sweating bodies tangled together after a particularly passionate session of making love, Sasori looked down at the teen laying beneath him and whispered a single word that his mind and body had been screaming at him to say for weeks. "Mine."
Deidara let the words sink in for a few seconds before chuckling and pulling Sasori down into a tender kiss. "Danna's," he agreed.
Smirking, Sasori moved his head down and nipped gently at the bomber's neck. "That's right, you belong to danna," he murmured softly against the tan flesh.
The word, so recently spoken by the puppet master, now caught Sasori off-guard. He'd claimed the blonde to make a point; to give substance to all the "I love you"'s that had been whispered between them for so many times. But why would Deidara…?
Another smile crossed Sasori's face as the answer dawned on him. The mighty Akasuna no Sasori did indeed belong to this hyperactive bomber. He'd been the blonde's ever since he let Deidara wear his clothes, since he let the blonde sit at his feet or sleep by his side; hell, the blonde had probably captured him as soon as they were in the same room, without the elder man ever realizing it. Deidara had as much right to claim his master as the Akasuna had to claim the bomber.
With a quiet laugh, Sasori pressed another kiss to Deidara's lips. "Yours."