If you're wondering about Tsukishima's qualifications for said theory, he's had his share of experiences with cats. He might not have ever owned a cat himself, but his childhood (and current) best friend, Yamaguchi Tadashi, has owned several cats while growing up. If that isn't enough, Tsukishima grew up in Miyagi. There are tons of stray cats in Miyagi. It's just enough countryside to give the little felines space to roam and just enough city life to reap the benefits of expired restaurant food.

And no, his evidence isn't as simple as Kuroo purrs at Tsukishima's touch or that he loves tuna. His evidence is substantial. Evidence that only cat owners would understand. Or, in Tsukishima's case, those living a life constantly surrounded by both domesticated and feral cats. Besides, more than half of the world's population likes tuna. And let's be honest, who wouldn't purr at Tsukishima's touch?

The first piece of evidence Tsukshima noticed almost immediately after the two moved in together. They chose an apartment in a high rise building in the heart of Tokyo. It's a short walk to Tsukishima's university and close to the subway Kuroo takes to his firm when he has to be in the office. Their apartment is a two bedroom apartment with the second bedroom acting as Kuroo's home office and a nice balcony off their master bedroom.

It took Kuroo a few mornings to actually display this behavior. It took Tsukishima a few nights to pin point the familiarity of it all. The first week was packed with unpacking, eating take out, and enjoying their...alone time...together. But once their things were settled and the banality of life resumed Tsukishima noticed it.

Each night Tsukishima and Kuroo would lay down together to sleep, but soon after those first few mornings Tsukishima would wake without Kuroo by his side. Now, every morning Tsukishima wakes to catch Kuroo outside on their balcony. Just looking. In the winter, Kuroo's face is almost touching the door, too cold to open or sit on the balcony comfortably. In the beginning Kuroo would hear Tsukishima stir before Tsukishima had the chance to catch his stare. Those times Kuroo's eyes would be on Tsukishima faster than he could find his glasses. Before Tsukishima can join Kuroo out on their balcony Kuroo would already be on his way inside to join Tsukishima back in bed or offer to make breakfast for the younger boy. Other times Kuroo is so enthralled by what's going on outside Tsukishima can sneak up on him and try to get a glimpse of what has his boyfriend's full attention.

When Tsukishima was younger and would stay the night at Yamaguchi's house they would stay in his bedroom on the second floor. Every morning, without fail, Tsukishima would wake to find at least one of Yamaguchi's cat's perched on Yamaguchi's window sill. Like Kuroo, there were times when Tsukishima would find his glasses and put them on only to find feline eyes staring back at him. Other times, Tsukishima would make it as far as placing his feet on the floor before Yamaguchi's cats would notice.

When Tsukishima asked Yamaguchi about the behavior his best friend shrugged. He said all of his cats liked his window. They seemed to like looking out, being higher than the world around them. By the time the two boys were in high school Tsukishima knew to wake without sound so he could catch a glimpse of Yamaguchi's cats. He'd stare at the cats staring out the window for what felt like hours.

Their focus was almost unnerving to Tsukishima. The minute Yamaguchi would stir the cats were at his side, begging for their breakfast. Yamaguchi would leave Tsukishima, leading his two kitty children down to their food bowl. Tsukishima would look out the window, hoping to be swept away in what the cats were mesmerized with just minutes before.

Kageyama had a dog. There were times, albeit times that Tsukishima tries to forget, that Tsukishima had spent the night at his former setter's house. He never once saw Kageyama's dog with such focus or such curiosity as Yamaguchi's cat's had for the outside world. That's when Tsukishima knew he was a cat person.

The first few mornings caught Tsukishima off guard. He always knew Kuroo was a morning person, but it was his first glimpse of what type of morning person Kuroo is. Months into their new life together Tsukishima learned to wake silently again. He keeps his glasses closer on his nightstand than before. A little lower for easier access. Just to see Kuroo look out the window.

It's one of the only times Kuroo is still (when he's awake). He's eerily still, eyes as focused as Yamaguchi's cat's. His head might move to follow something outside, but it's never rushed, always slow and steady. And if Tsukishima does get the pleasure of catching Kuroo's quick reflexes, he can only guess what could be so interesting to catch his boyfriend's attention.

So, exhibit A: Kuroo Tetsurou likes to stare outside. Not the strongest evidence, but Tsukishima is just getting started.

To piggyback off of Exhibit A, the more comfortable the two became living together the more Tsukishima realized just how much Kuroo doesn't sleep. During the night, that is.

Sure, the two still lay down together to go to sleep at night, but Tsukishima wakes in the middle of the night to find the second bedroom light on more often than not. At first Tsukishima had been mildly offended that Kuroo couldn't seem to stay one full night in bed with him. Is he a blanket hog? A snorer? Does he kick in his sleep?

It wasn't until Kuroo agreed to try to stay in bed all night that Tsukishima realized Kuroo had been doing Tsukishima a favor. He'd toss and turn, huff and puff, turn on the light to grab for his pen and paper left by his bedside for any ideas that come to mind. Definitely the opposite of the serene Kuroo he watches in the morning.

You have to understand, the longest the two boys had ever spent together were during their training camp in their high school years. They weren't even sleeping in the same room, let alone the same bed. After that, weekend trips here and there happened, but Tsukishima found that if Kuroo pushes himself to the limit, uses up all of his energy for the day, he will sleep like a normal person. Those weekends were usually filled with exhausting activities (both clean and dirty), so Kuroo had been unintentionally leading Tsukishima to believe he operated on a normal human's sleeping schedule.

But instead of a normal human, Kuroo Tetsurou is a cat trapped in a human body, so of course he's up at all hours of the night. He did hide it well at first. Timed his naps for when Tsukishima settled into bed and timing to wake from another just when Tsukishima would be stirring in the morning, maybe an hour or two earlier.

When Tsukishima first asked what Kuroo does during the night he only received a shrug in response. "This and that," his boyfriend explained when Tsukishima pushed a little harder. Turns out, Kuroo does most of his heavy thinking, heavy planning for his cases in the middle of the night. It seems that's the time he works best.

It's not that Kuroo has insomnia, either. Kuroo sleeps. Kuroo sleeps a lot. Which brings up Exhibit B: Kuroo takes naps throughout the day. What do they call those? Oh yeah... cat naps.

Tsukishima is no longer surprised when he comes home from class to find Kuroo sleeping in the sun their large windows let in. It's amazing that no matter the time of day, if Tsukishima comes home to find Kuroo napping, the older boy is always in the sun. If Tsukishima makes multiple stops home, it's not uncommon to find Kuroo napping on the floor wherever the sun is shinning at that time. The first time usually laying closer to their couch. Then, the second time Kuroo is still napping, but laying closer to their entertainment center, making sure to stay in the sun's warmth. Luckily for Kuroo, their apartment faces the east. He gets the most out of the sun.

There are other times that Tsukishima comes home and Kuroo is working away in his office, don't start thinking Kuroo is lazy by any means. He's fortunate enough to have a somewhat loose schedule. The days that Kuroo has court or meetings in the firm are the nights that Tsukishima gets to cuddle with Kuroo a little longer in bed before the older boy slips away in the early hours of the day.

Of course, there are other nights that Kuroo reminds Tsukishima he is most definitely human with human (one could argue animal) instincts... those nights Kuroo stays in bed all night. Again, the exerting of all of his energy...

If Kuroo had the chance Tsukishima thinks he would nap the day away. One to two hour naps littered in between eating, paperwork and spending time with Tsukishima. Especially since Kuroo's getting older, less spry. The naps are a little more consistent, but never too long. Tsukishima comes home, finds Kuroo asleep and places his hand in his boyfriend's hair. Kuroo purrs at Tsukishima's touch, stretches his entire body to it's limit, and smiles up at his boyfriend.

And when Tsukishima gets the opportunity to take a nap he almost always wakes to a surprise near his face.

Exhibit C.

It's nothing too extravagant. And it's usually nothing that Tsukishima is actually happy to see. Tsukishima wouldn't consider them gifts as much as mementos. Kuroo is adamant on calling them presents.

Sometimes it's an old sock Kuroo finds on his way home from work.

"It reminded me of the pair of socks you wore the first time you stayed at my house!"

Or a bone from a chicken wing he ate during lunch.

"I thought you might like it since a chicken is like a tiny dinosaur."

Okay, so the sock wasn't the greatest present (wasn't the worst, either), but it's nice to know Kuroo is constantly thinking about Tsukishima.

And Tsukishima keeps every single present Kuroo leaves, no matter how silly. He has rocks, pressed flowers, any dinosaur figurine Kuroo finds in quarter machines, a petrified lemon, bells of any variety, rolls of athletic tape that Tsukishima no longer has a use for and over a dozen chicken wing bones.

Not to say Kuroo doesn't give extravagant gifts. Tsukishima has woken up to a new pair of headphones, an Mp3 player with more storage space, several mixed cd's, and a few fresh picked strawberries. Well, Tsukishima doesn't keep the strawberries... for very long. It takes about 2 hours for a strawberry to digest.

Tsukishima thinks all of his presents from Kuroo are extravagant, but don't tell Kuroo that.

Yamaguchi used to tell him stories of his cats leaving dead birds at their doorstep. Once, Yamaguchi woke to find a dead mouse on his pillow. He had bragged to everyone in his class for weeks.

Tsukishima made a habit of feeding one of the stray cats in his neighborhood his leftover lunches. He, too, was prized with a dead animal on his doorstep one evening. His fondness for cats grew.

Tsukishima remembers reading an article about cats and giving gifts. The article said that cats usually bring their owners gifts to show their admiration for their owner. Sometimes, it's to show off their catch. Since Tsukishima is the designated bug killer of the house, it has to be some twisted version of the first option. A way for Kuroo to show his love for the younger boy, right?

Tsukishima's afternoon class is canceled so he comes home to find Kuroo sleeping dangerously close to the door. He tip-toes over his boyfriend, careful not to graze the sleeping boy. He sneeks a few pictures on Kuroo in a location he's never seen him nap before (for evidence) and creeps into their bedroom.

It's become a game for Tsukishima. Will Kuroo have a present prepared today? He didn't know about Tsukishima's canceled class so it's not like he knew he would be leaving a present today. He purposely didn't call or text Kuroo. A part of him wants to see if Kuroo has a stock pile of presents he uses in emergency situations like this. Another part is interested to see what will happen if Kuroo doesn't have a present prepared.

When Tsukishima wakes up from his nap he finds a small box sitting on Kuroo's pillow.

He opens the box and finds a ring.

AN: Have you ever watched a cat look out the window? Mine does it literally every morning. For hours. Sorry this is so jumbled and rushed, it just all oozed out I guess..