Okay, this is the one shots, Kakairu style. There will be another post with non-Kakairu one shots. In the interest of being brief, I'm going to hit the high points, but most of the authors on here have other stories that you should totally read.
Festival Fun by Kiterie
Kurenai gets both Kakashi and Iruka to help her with the dunk tank for the children's festival. I'm bad at summaries. Anal, COMPLETE, Voy, Yaoi
Lonely Tears by Nayru-Kleinefee
Iruka believes that it’s better to suffer than to lose, better to hurt than to cry.
Truancy by Mistress Quickly
"Some day, you’re going to get me fired. You know that, right?"
Iruka Umino snorted and licked a line up the neck he’d never seen but had tasted, countless time, blindfolded in his bedroom, in the deserted classroom, in the dense forest surrounding the village.
"Am I at least making it worth the risk?" he said, nipping just under his lover’s ear.
Untitled by liadhdain
When his anger over things he can't change becomes paralyzing, the only thing he can do is go home to the man he knows is waiting for him.
Fighting Fair by Realnobiki
Kakashi and Iruka continue their fight after Kakashi nominates Team 7 for the chunin exams.
KakaIru Valentines Day Challenge by Chibi-zoe
Drabbles for the Valentine's Day 2008 Challenge Prompts
I love the way you abuse me by combine2rinraw/Sisco
Kakashi comes home from a frustrating mission and he needs to take it out on someone. WARNING! Disturbing content!
Lies by H. E. Gray
It's nearly pathetic how easy it is to fool a village full of ninjas. Iruka lies so much that he can hardly remember the truth.
Proper Diversionary Tactics by Drop of Poison
Kakashi is setting a cruel trap for his team of genin to "teach them a valuable lesson" when Iruka steps in to stop him. However, with a few clones, Kakashi easily manages to keep Iruka busy with other matters.
The End by Jam and Jelly
A short piece about Kakashi and Iruka's last moments. Also Raidou and Genma.
Telephone by Pru (I think that's the author's name)
It's rough being Team 7. I know the summary doesn't sound very interesting, but this is probably the funniest "Team 7 finds out" story I've ever read.
In Her Eyes by Blue-iceland
Sakura’s thoughts about her sensei’s love life
Conversations by parenchyma
Sequel to
Don't Look! Iruka attempts to explain his relationship with Kakashi to Genma with...mixed results.
Fair Play by Pirate Burn
[KakaIru] Iruka hurries off one morning and forgets something important. If Kakashi's mystery is his face under his mask, this is Iruka's. (no spoilers, pure jounin love)
A Touch of Velvet by Bitter Eloquence
There is more to Umino Iruka then meets the eye. A core of steel lays beneath that sweet and seemingly innocent exterior and the soft façade of velvet wrapped around the iron fist is thin enough to see at points. Minor Kakashi Iruka Hints
The “Girl” Whose Brother Was a Fox by Kare-neko
FCUKED up Fairytales… a Naruto Crossover-crackfick/mindfuck.
Making Memories by mushroom18
“ARE YOU PLANNING SOMETHING WEIRD?!” Naruto demanded at last as he and Kakashi walked to the dining room, pointing an accusing finger at the jounin.
Kakashi’s visible eye gleamed. “Oh, I just wanted to have dinner with Iruka-sensei. It’s been a while. So, how did your search go?”
“SO THIS IS WHERE YOU’VE BEEN ALL THIS TIME! YOU REALLY PLANNED TO LOSE US IN THE WOODS SO YOU COULD DO FUNNY STUFF TO IRUKA-SENSEI, DIDN’T YOU?!"
Kakashi feigned a disapproving look. “Really now, you’re a trained ninja, you shouldn’t get lost too easily-“
“-LAZYBONES! PSYCHO! PERVERT!”
“…Says the boy who transforms into a naked female with abnormally large breasts for fun.”
“Did someone say breasts?” Iruka peeked from the kitchen, eyes narrowing dangerously.
Wrong by earwensilimaure
They thought Kakashi was seme. Always, always on top. Being Uke? That was just plain impossible.
Wrong.
It was he who was above the sharingan user, except when the man was in a ‘riding’ mode which he didn’t mind at all. But the chuunin was the one in command. The only one that knew that Kakashi loved - no, was addicted to bottom.
Kakashi previous lovers hadn’t understood that. He was the sharingan user, the copy-nin.
Attempt no. 173 by Micah_n10
This was, Naruto decided, his best idea ever. He would once and for all see beneath Kakashi-sensei’s mask. Of course, Iruka-sensei wasn’t part of the plan. But he can work around that… right?
On Little Cat Paws by Kita the Spaz
How he had let Naruto talk him into this, he would never know, but it had stared out as a simple plaint from the dobe that his Iruka-sensei was acting weirdly. He hadn’t even offered to take Naruto out for ramen. It had started as an argument; Sasuke informing the loudmouth that Iruka-sensei was probably tired of filling his endlessly empty gut and Naruto declaiming that there was no way it could have been such a thing. Then it had become a matter of Naruto boasting that he would follow Iruka around ‘improving his stealth,’ (as if it were possible for the idiot to be stealthy.) and find out what was causing the chuunin to act oddly. Somehow, he still wasn’t entirely sure how, it had devolved into a bet on which of them could remain undetected by the teacher long enough to effectively spy out why Iruka was acting out of character.
Red-Handed by steveness2310
He needed to see a man about a horse.
Which, in some underneath the underneath way, Kakashi supposed was true, because while he did not have to see a man about a horse, his business did have something to do with a dolphin--even though said dolphin was more of a man than an aquatic animal. Really, he had reasoned, it would not be his fault if his students didn’t understand that his excuse was a complete lie, as he had been trying to teach them from Day One that appearances were just that: appearances. And it wasn’t as if his business hadn’t been very urgent indeed, and in everyone’s best interest, because if he was not bent over that desk post haste, he was going to be quite impossible to live with.
Or, he amended as he lost all higher brain function, as long as Iruka kept on doing that thing with his tongue.
How to File Form 39-B by thehoyden
The first time Iruka met Hatake Kakashi, he was still on some pretty good painkillers.
Hunter's Moon by Maldoror_gw
Iruka's hand darted from the bento box to his weapon satchel. Twenty plus years of ninja training didn't go to waste, even if he nailed his opponents with chalk rather than shuriken nowadays.
He scrambled into a wary crouch, the food forgotten. A quick check of his surroundings revealed nothing suspicious. That didn’t mean the danger wasn’t real. But there weren't many approaches open to an enemy, all the way up here. The trapdoor down to the level below was closed and there were no other rooftops nearby. This was the highest building in Konoha, bar the Hokage's HQ; it was the public library, with a decrepit tower observatory that twisted its way up towards the stars. It was right next to the school, so Iruka knew the place well. The roof's occupants couldn't be seen from anywhere else in the village, which was why he and Kakashi had met here a few times in the past couple of years to eat, chat and watch the stars before-
Iruka's eyes twitched back towards a spot between two chimney flues twelve feet away, a slice of night he'd already examined. Instinct had made him look again, to find that moonlight and darkness had solidified into a familiar figure.
"Kakashi?"
Firsts by Guardian of Jupiter
The firsts are not always the physical things. Sometimes, they leave impressions much, much deeper than that.
Three is... most definitely not a crowd by ranty_rie
Kakashi’s a kinky bitch. Both of them. Iruka doesn’t particularly mind.
Fire and Ice by jitkajaylor
Freezing heat and burning cold. With ninjas, nothing is what it seems.
Mortal Sin by Mange_wolf
After a mission, Kakashi and Iruka decide to unwind.
Libido by Life_symphony
KakaIru. Iruka mistakes pills for aspirin.
Whew, only one more to go.