Air
If Gai was the earth, Kakashi was the air, fleeting, touching people's lives and then going away, offering no proof that he was even there at all and blending into the background so well that it took the earth to come and make him something solid again.
Apple
It was strange that their relationship had started with an apple; Gai had tossed it at Kakashi after one of their challenges, telling him that he needed to eat more if he was to become strong enough and Kakashi realized that yes, there was someone out there who cared and now, for their anniversary, Kakashi had tossed Gai an apple and asked if he was strong enough yet.
Beginning
In the beginning, there was a cynical, burnt-out preteen who had thought that he had seen it all and a green-clad youth with enough energy and enthusiasm and life to appeal to anyone; now, it was much the same, save there were older, stronger, and a little wiser.
Bother
Things always seem to affect Gai, but only one thing truly gets under his skin and bugs him, that being that nothing ever seemed to bother or even affect Kakashi and sometimes it's hard for even him to tell where he stands with the Copy-Nin.
Day
Kakashi's favorite time of day was in the early morning, when he got to recline on the back porch of his family's dojo with a cup of hot coffee and watch Gai, and sometimes Lee, start training; Kakashi only claimed it was so because of the coffee.
Dark
Kakashi was such a dark and brooding individual that it was almost comical to see him walking down the street with Konoha's Green Beast, who was the sun personified.
Despair
Gai, as a rule, tried not to hate but every time he looked into Kakashi's eyes and saw the utter despair residing there, he hated; hated Sakumo for pushing him so hard, hated Obito for giving his life for Kakashi's, hated Yondaime for leaving, hated the Third for dying, hated Team Seven for being too good, hated Kakashi for dwelling on things that coult be changed, hated himself for not being able to help rid Kakashi of his soul-eating despair.
Door
There were some doors in the Hatake home that just were not meant to be opened; Gai understood this and, in turn, allowed Kakashi access to all of his home and himself.
Drink
No matter how eager they were or how much Kakashi cursed and begged, Gai always took the time to sit back and drink in the sight of his lover open, needy and vulnerable, savoring it as much as possible until Kakashi blushed and dragged Gai down to his lips, complaining about Gai always staring at him.
Duty
They both knew that someday, they might die at the other's hands, that was just the way it worked; there were some things that were just more important than love, at least to a shinobi.
Earth
Kakashi has always compared Gai to the earth, solid, steady, immovable, strong on his own and yet not afraid to accept another's help; to Kakashi, Gai is the earth, one of the few constants in Kakashi's fleeting little wisp of a life.
End
Kakashi hated endings, they meant that something was finished, over, lost, gone and often Kakashi was left alone; he lived in fear of the day he finally did something seriously wrong and his relationship with Gai ended.
Fall
Kakashi remembered the feeling of pain and torture and he couldn't move and he was sinking through the water and he was going to drown, but then Gai was there, pulling him out of the water, holding him as he sat up gasping after a nightmare and he knew, Gai would never let him fall.
Fire
Kakashi was well-suited to Konoha, he was fire personified; he burned, changed, affected everything he touched, he drew you in with the promise of light and warmth and compassion and left you hurting, gasping and ashamed that you hadn't seen it coming and even though it had been painful, you just wanted to go back for one more taste of that light and warmth.
Flexible
They were both flexible, it was one of the requirements for shinobi, either you adapted or you were killed; however, Tsunade refused to pay for the repairs to Kakashi's bed after he and Gai had broken it during "flexibility training".
Fly
As Kakashi sped through the trees, he felt like he could fly if he just kept going aster and faster and higher, adrenaline racing through his veins, he was going to take of into the sky, away from here, never to come back... until Gai wrapped his arms around him and told him to come back, grounding him as Gai always seemed to do.
Food
Gai had once despaired of ever getting Kakashi to eat enough, the man was too thin, all skin, bones, muscles and scars; now, all he had to do was carry a snack into the bedroom and Kakashi was there in an instant, ready to share whatever it happened to be with Gai.
Foot
It was a well-known fact that Sharingan Kakashi had very few weaknesses; it was slightly less well known that one of them was that he was a sucker for a good foot massage, something Gai found highly amusing.
Forget
Whenever Gai wants to find Kakashi, he always looks at the cenotaph first, even before checking the Hatake house, because that is the one place where Kakashi is almost guaranteed to have lost track of time, staring at the names carved there and thinking about the past.
Green
The Green Beast of Konoha - like all the rest, Kakashi had thought the title came from the green body suit, until he first set foot in Gai's house and marveled at all the plants all around, realizing that maybe the nickname had nothing to do with spandex and more to do with life.
Head
It was one of Kakashi's hidden talents, the ability to bring pleasure and so he used his mouth and lips and tongue to say all the things that he wouldn't manage to say out loud, to tell Gai all the things he needed to know and looking up into Gai's fiery, pleasure-darkened eyes with his cock in his mouth, he could see Gai understood.
Hollow
Kakashi was fascinated by the hollow at the edge of Gai's collarbone so he pulled Gai down as he pounded into him and used it to muffle his cries and whimpers, all the while sucking and biting, determined to leave a mark that he could explore again later.
Honor
They always pulled their punches in their matches, it was a matter of honor between the two; they would train themselves and each other, becoming stronger for each other.
Hope
It was one of the most important things Gai had brought to his life, something Kakashi had given up on long, long ago and yet something that Gai never failed to believe in, which was something Kakashi couldn't think of faulting him for, because it was something that was just Gai and something Kakashi needed as well.
Light
Gai brought light into Kakashi's life, through the windows he left open, through the door he propped open to let in the scent of the earth, through his blinding smiles, and his "Nice Guy Pose" but mostly though his enthusiasm and pure enjoyment for life, something Kakashi had never felt but was beginning to appreciate just the same.
Lost
Kakashi had lost so much in his life that he wasn't sure what he would do if he lost Gai as well, but Gai always seemed to have this aura of immortality about him that wiped away all of Kakashi's fears; Gai was strong, Kakashi wouldn't loose him.
Metal
Kakashi had a metallic scent clinging to his skin, something he didn't like but could do nothing about; when he found out that Gai also had traces of metal scent on his skin, he decided he could deal with it, since it was a reminder of his lover.
New
This was all something new and strange and a bit disconcerting to Kakashi, who had always been afraid of something so fragile and meaningful, but maybe something new was just what he needed.
Old
After the death of the Third, Kakashi tried to avoid Gai and, when Gai finally tracked him down, he couldn't even say why; he couldn't find the words to say that now, Gai was the only person in Kakashi's life who was still alive and it was an old, old fear that if he stuck around, he would bring about Gai's death as well.
Peace
It was when they lay in bed wrapped around each other every night; it was when Kakashi would fall asleep on the couch and wake up covered with a blanket; it was when Kakashi would call Gai an idiot and bandage his hands after he overdid it in training again; most of all, it was when they simply sat together on the roof, looking out over the village and just existing for a while.
Poison
Sometimes, Gai was like poison in his veins, something he needed, wanted, was afraid of, but couldn't live without and there was just nothing he could do, for Gai was the antidote as well as the toxin.
Pretty
Kakashi was so pretty, thought Gai, so pretty when he was bare, open, vulnerable, riding Gai's cock as if it were the only thing he had ever wanted, head thrown back, eyes closed and the noises he made, moans, whimpers, cries, something that could have been a curse, a shaky, needy version of Gai's name... so pretty.
Rain
Kakashi hated the rain because every time it rained, something bad happened or someone he loved died or some other horrible thing, so on rainy days, he curled up in bed and hid from the world; then Gai had come in one rainy morning and dragged Kakashi out of bed and outside, and at the sight of Gai dancing and laughing in the rain like a child, Kakashi began to think that maybe, maybe he didn't hate it as much as he thought.
Regret
Kakashi had so many regrets in his life, so many people that he had failed, Obito, Rin, Yondaime, Sasuke, Sakura, Naruto; and he hoped and wished and prayed with everything he had and everything he was that Gai would never, ever end up joining Kakashi's list of regrets.
Roses
For their one-year anniversary, Gai had gotten him a bouquet of roses; it had been so unexpected and yet so completely Gai that all Kakashi could do was smile, one of his few honest and open smiles reserved especially for Gai.
Secret
Kakashi had many, many secrets and guarded them fiercely; Gai was one of the few people in Kakashi's life who never tried to find out his secrets, instead waiting for Kakashi to tell him on his own, because that made the knowledge that much sweeter.
Snake
Before, Kakashi never would have thought of Gai as snake-like, that word more suited to Orochimaru than the infamous "Green Beast of Konoha"; now, Gai has made a habit of coming up behind him, snaking his arms around his waist and trying to completely wrap Kakashi up in his embrace.
Snow
The snow that was falling was so pure and white and magical and perfect, except in the area around Kakashi where the pure white snow had been defiled and stained with red and Kakashi felt like weeping at the destruction to something so innocent and pure.
Solid
Gai was always there in Kakashi's life, challenging him, healing him, fighting him, helping him, but this was how Kakashi liked Gai best, as a firm, warm solid presence at his back, both in bed or on a battlefield.
Spring
Spring was undoubtedly Gai's time, with the world full of love and life and it was without a doubt the most magical time of year, everything growing and blooming; Gai always dragged Kakashi and Lee out on his spring nature hikes to just look and feel and experience the world with him because he wanted to share the magic of springtime with his family.
Stable
Gai was more stable that Kakashi, probably because he had led a fairly normal ninja life; Kakashi had been shoved into the ninja world half as soon as other children and almost as soon as he did, things began going wrong and it wasn't really a surprise that he was unstable - the surprise was that Gai had managed to successfully counterbalance Kakashi.
Strange
Gai was strange, everyone knew that and a lot of them tended to make fun of him; what they didn't realize was that all jounin are a little bit strange, a little bit odd, it was just some way to define themselves aside from killing people and in that aspect, Gai was no stranger than anyone else.
Summer
Summer had always been their time, with less missions, a break from teaching and a lull in responsibilities; summer days were the ones where they lay in the sun after a challenge, enjoying the warmth and presence of another person who appreciates the season just as much.
Taboo
They never said it, as if, since they didn't say those words, they would always come back home safe and sound; that was why they never wished each other "good-bye" before a mission.
Ugly
Gai knew that he wasn't the most physically desirable person and in his rare contemplative moments, he wondered if he was worthy of the beautiful Hatake; but Gai knew there were different kinds of beauty and maybe he wasn't as undesirable as one would think.
War
War was a constant in the life of a shinobi, war with other shinobi, war with other countries, war with demons, but most of all war within oneself, trying to find purpose in a life where one spends their entire adulthood trying to kill each other and as with all war, if one isn't paying enough attention, it will kill you.
Water
Gai sometimes wondered how someone like Kakashi could be such a contradiction in himself, like fire one second and water the next, flowing, moving, changing, never holding still, and with so much going on beneath that one couldn't even begin to imagine, so deep and calm that it would lull one to sleep and then he was crashing and breaking and tearing you to peaces and, as always, you never really knew what to expect.
Welcome
Gai took everything Kakashi did in stride, which was why Kakashi stuck with him; he knew that even if he came to the door bloody, beaten, broken and disgraced, Gai would still greet him with a smile and usher him inside.
Winter
Winter was Kakashi's favorite time of year, when everything was cold and numb and Kakashi didn't have to put as much effort into not feeling since the cold was assisting in making him numb; winter also meant that Kakashi could convince Gai to stay in bed longer, the two of them cuddled together under the blankets, sharing their heat and peace with each other.
Wood
Kakashi could tell Gai's mood by the state of the wooden posts in training field six; if they were just lightly marked, everything was fine; if there were several deep grooves, Gai was a bit frustrated or worked up, but he had worked it off already; if they were cracked and split, Gai was angry and probably running it off; but if the wood was no longer recognizable as such and dotted with spots and splashes of red, whatever was wrong was probably Kakashi's fault - Gai only bled for Kakashi.