Title: Prerequisite
Fandom: Naruto
Rating: M for Rampant Sexual Humor
Warning: Discussion of body parts, bad humor, making fun of Sasuke, Kakashi abuse, no beta
Disclaimer: I own nothing here.

REVISED VERSION: As of 2/4/08, edits were done regarding word-flow and pacing. I also added to one scene as I wasn't entirely happy with the original.

Kakashi sat down in the rickety little classroom chair that was sized for someone at least two feet shorter than him and opened the book in his hands. It was large and thin and floppy, more like a coloring book than his normal reading material

"Okay, then," he said, "I think we're supposed to start with…"

He paused and turned back to the beginning of the book to double-check its miniscule table of contents. He flipped a few pages forward again and nodded in satisfaction.

"Ah, here," he said and turned it around to show the illustration on the inside, "This is the female genitals, otherwise called the –"

Sasuke stood up so fast his chair knocked over and stormed to the door, refusing to even look his teacher in the face.

Kakashi sighed, lowering the book. "Sasuke," he called out, just as the teenager's hand wrapped around the door knob, "You won't be authorized to go on the mission unless I verify that you've had this lesson."

Sasuke froze with his hand still on the knob. His head was down and his shoulders heaved with his near panicked breathing, but he didn't make the final effort to leave the classroom.

Kakashi gave Sasuke a moment to compose himself and went back to the "education aid" he'd been given. There'd been several for him to choose from, actually, but this one had been the shortest and least technical. The dumbed down version, in other words, which he felt would be a great asset when he had to give the same lesson to Naruto next.

"Why?" Sasuke demanded after a while, in a strained voice that had undoubtedly been pushed out from under the sheer crushing force of teenage embarrassment.

Kakashi scratched idly at the back of his head and considered the ceiling. He could sympathize with Sasuke's reluctance and horror; sitting down for a talk about human reproduction with a student was the last thing Kakashi had wanted to do today, himself. But that didn't mean he was going to let Sasuke get out of it.

"The mission will require questioning patrons and employees of an adult district," he said. His expression became more serious under the mask as the real importance of this lesson pushed past his annoyance with having to do it. "It may involve undercover work that could potentially expose either of you to a sexual situation. We need to be sure you understand what that means and how to deal with it, so that it won't interfere with the mission. Normally this would be left up to your parents, but..."

Kakashi trailed off and shrugged.

Sasuke spun around in a flare of dramatic movement. His eyes were narrowed, his brows were tightly drawn together, his mouth was a tense grimace, and his hands were clenched into fists. Kakashi couldn't decide if this made him look morally offended or constipated.

It seemed for a moment that he might yell, probably at Kakashi's casual dismissal of his family's deaths, but when he did speak, the words sounded like they were being ground out from between two rocks.

"That doesn't explain why it has to – to cover --" He made a stiff gesture at the book Kakashi held and, presumably, the illustrations of various naughty bits it contained. "-- that sort of stuff. It's completely unrelated."

Kakashi stared.

The boy, he realized after a few minutes of dead silence, was completely serious.

"Sit down," Kakashi said finally and began rummaging through his multitude of pockets and clever hidey-holes for a writing implement. The two ballpoint pens he normally carried about his person weren't in their usual spots, which meant he'd either forgotten to put them back the last time he used them, or, more likely, they'd been called upon to double as weapons and were probably still lodged in corpses somewhere.

Sasuke eyed him as if he was going to pull a naked woman out of his back pocket and didn't move. Kakashi, after a bit of digging, managed to locate a red crayon of unknown origins from the inner seam of his vest. He gave Sasuke a thoughtful look.

"I guess you can leave," he drawled, and Sasuke had the door open and was two steps into the hall before Kakashi had finished, "I'll just explain to Naruto why you couldn't go on the mission."

The wind of Sasuke's sudden return ruffled Kakashi's hair.

"Talk," Sasuke spat, violently yanking his chair back up onto its legs. He perched on the very edge of it, poised for flight, like he expected Kakashi to start flinging explosive tags and poisoned kunai in his direction any second now.

Kakashi smiled brightly. "Here," he said, holding out both crayon and book to Sasuke, "You're supposed to color in the parts while I read them off."

"…I'm going to stab that crayon in your eye."

"Sasuke-kun, the mission–"

Sasuke snatched both items from him, nearly ripping several pages in half. The book went into his lap where the picture and all the glorious secrets of anatomy it revealed were completely hidden under his forearm. He stared silently at Kakashi and Kakashi imagined he would have that exact same expression if someone were pulling out his fingernails.

"Well," Kakashi said, letting out a sigh. This wasn't going to work. He rubbed his chin thoughtfully, reminding himself of why he couldn't just read aloud a chapter of Icha Icha Paradise and be done with it.

A little bit of red started to appear on the edges of Sasuke's pupils. So impatient.

"Hmm, how about…" Kakashi said slowly, "You tell me what you do know about sex, and I'll fill in the gaps." Surely a boy Sasuke's age would have some idea of what went on in the bedroom. Even if it was only gleaned from dirty talk around the bathroom or the ninja headquarters.

Sasuke's stare became even more intense.

"It is," he said, "The sacred expression of love," he continued, eyes narrowing, "Between a man and woman."

He paused and then added meaningfully, "After they are married."

Kakashi dropped his hand to his side. After a few minutes, it became apparent that Sasuke didn't intend to say anything more.

"I see," Kakashi said, deadpan. "In that case. The female genitals are called the vagina, when aroused —"

"Yeah, yeah, I know all about that," Naruto said, waving his hand dismissively as if he weren't blushing and fidgeting in his seat, "Your penis into her hole, wear a rubber, and respect her in the morning or she'll kick your head in. Iruka-sensei explained it to me."

Kakashi rather hoped that wasn't exactly how Iruka-sensei had explained it, but all that mattered was that he wouldn't have to go through this talk a second time. He was pretty sure Sasuke wasn't going to be able to look him in the eye for the next five years.

"Good, good," Kakashi said, beaming. Maybe he would be able to wrap this up in time for an early dinner after all. "That should cover all the important parts. Did you have any questions?"

"Um," Naruto said and shifted again, gripping the underside of his seat with both hands. Kakashi nodded encouragingly.

"Do you know why..." He hesitated and then plowed forward with full strength, "Do you know why some guys like to stick their things into other guys' butts?"


"I mean," he continued, obviously warming to the subject when Kakashi didn't speak, "Doesn't that hurt? And isn't it really gross? I mean, that's where –"

"Naruto," Kakashi said, holding up one hand for silence. Naruto cut off and looked at him expectantly. Kakashi pondered his options, the most appealing being to switch with the nearest desk and sneak out the window while Naruto was distracted.

"For some men, that is simply what they enjoy the most. It is a matter of personal taste," he said finally, suddenly ridiculously glad Sasuke hadn't known enough to ask these questions too, "Also, there are ways to overcome the discomfort, such as using oil and keeping yourself clean."

"Oh," Naruto said, still looking confused. He quickly perked up again, though, clearly undaunted by Kakashi's vagueness. "Okay, so what about mouths? When a guy uses his mouth on a girl, how does that —"

The next day, Sakura brought Kakashi a signed letter from her parents. He took her out for dinner in thanks.