The sound of Iruka's heavy breathing always made Kakashi feel content. With what? He didn't know. He didn't care to know, nor did he wish to expend any effort in the process for determining that unknown. Iruka made him happy. End of story.
But there was this one day where a very inspired Kakashi came home after purchasing the newest volume in Jiraiya's collection, only to find a miserable Iruka lounging on their bed. Kakashi thought it would be very interesting to conduct an experiment which includes obtaining the result of a potentially amused Iruka. Sadly, that attempt had failed, and Kakashi had somehow found himself sleeping with Iruka's back to him. Not only was his experiment deemed a failure, but it had also turned out to be a very uneventful night, one where Kakashi thought his inspirations would be unfulfilled.
--
It all began at dawn, where Kakashi, unmotivated as always, had forgotten to accomplish Iruka's request to set the alarm for five a.m. Iruka had been too damned tired from their previous night's foreplay, and asked Kakashi for this one little favour. Iruka ended up waking at seven a.m. instead, disturbing the entire neighbourhood let alone their apartment with his rage.
So far a bad day.
Now this bad day couldn't just end there, no. it had to expend infinitely throughout the day, mocking Iruka at each passing hour. His students had pulled pranks on him all day. His co-workers had acted strangely around him, snickering or gossiping, or a strange combination of the two and quickly walking away. Until, of course, one of the chunnin actually had enough courage to approach Iruka and inform him that he had sat down on a painted school bench, and the brown colours had been absorbed through the fabrics over his rear and his back. But mostly covering his rear, so it had appeared as if Iruka had shat himself sometime during the day.
Perfect! Absoloutely perfect! First I wake up late, thanks to Kakashi, whose going to be sleeping on the goddamned floor tonight; then the children decide to assassinate me with their adolescent humour, and now there's a rumour going around, reaching every ninja in the village by now, that I've shat myself!
And to make matters worse, the strap of his sandal had snapped while he was running home, so Iruka had ended up tripping and landing face-first in a thick pile of mud. Now his face matched the colour of his ass. And he walked home barefoot, as he decided it would be much sillier to travel with only one shoe.
Iruka had showered once he got home, and collapsed on the bed, exhausted from his endless stream of bad luck. What had he done to deserve this? Had he disrespected a sacred temple sometime in the past? Had Naruto disrespected a sacred temple and used one of Jiraiya's get-out-of-this-fix-quick jutsus to transfer the misfortune to him? Or did the universe just decide to fuck with him for fun today?
And now his head was hurting from too much unnecessary thinking. Iruka began to drift off to sleep, closing his heave lids and silently praying for tomorrow to be an easier day. That's when Kakashi entered, and Iruka forgot all about his tired state, because the fury that resonated through him at that moment was powerful enough to heat one thousand bowls of instant ramen.
Cue argument:
"Why did you so blatantly disregard me?" Iruka snapped. "I specifically asked you to set my alarm for five a.m., and I find myself waking up on my own two hours later! I was suppose to go in earlier today to finish marking those assessment papers that Hokage sama instructed me to look over. I ended up having to skim through them. I had to skim – no thought process, no grammatical or logical deconstruction, because there was no damned time! Hokage sama will be extremely disappointed at my lack of effort in this, and what excuse shall I provide her with? That you didn't set my alarm the night before like I asked you to. And why? Because I was too goddamned tired from your late night fucking around, and I thought that I could trust you, which turned out, apparently, not to be the case!"
And Iruka's rant continued along similar lines of topic.
"Are you done yet?" Kakashi had asked when Iruka had finally paused to take a breath.
Iruka stared at Kakashi with murder in his eyes, screaming a verbal assault of mixed profanities.
"Well," Kakashi said, "I had just recently purchased a new release of one of Jiraiya's books, and I've discovered some interesting material that I would very much like to experiment with you."
Iruka was visibly fuming now. "This is exactly how the problem began in the first place."
"Ah, but in this you are wrong. You see, this would be material from a new volume, and last night . . . well, last night was my interpretation of what I'd remembered from my readings."
"Unbelievable." Then after a pause and a moment of murderous glaring, Iruka had announced that he was going to bed, and wished not to be disturbed in any way tonight.
Kakashi felt sad, though he decided that it would be wise not to further push Iruka's patience over the limit. After all, one could only take so much shit in one day before completely cracking and discovering oneself in epic depths of utter insanity. It may not seem like it, but there are times when Kakashi has a heart. Especially if he wants to be on good terms with his lover so he could get laid again. The sooner the better.
And that's how Iruka ended up sleeping with his back to Kakashi. Though this didn't last very long, for Kakashi somehow managed to manipulate Iruka's emotions with his ever-gifted charm. Which lead to many hot, passionate kisses involving a lot of tongue and as little breathing capacity as possible. Which late lead to other experimental matters involving certain sexual positions too creative to describe, but wow, Kakashi thought, he never dreamed he could get Iruka to express his vocal excitement this thoroughly in one night.
They ended up drifting off to sleep in each other's arms, Iruka laying as close as possible to Kakashi, and Kakashi listening to Iruka's breathing even out. And as for the experiment? Let's just say that Iruka ended up waking up late. Again. Thought this time, his anger was slightly less defined.