The first one happened when they were six, and neither was quite aware of it until they were back in their rightful places.
One moment, Naruto had been waiting for his kettle to boil, the next there were fast, insistent blows coming at him - he dodged, gripped the wrist and twisted, pulled hard with his body weight to send the stranger tumbling past him, then ran.
One moment, Hinata had been in position to defend against her teacher in Jyuuken, the next she was sitting on a tall stool in front of a stove with a half-opened cup of ramen in her hands.
Suddenly, she was blinking at the light from the door to the closet she was in opening, the cautious, stern expression of her teacher peeking in at her.
Suddenly, his kettle was boiling, and he had no choice but to quickly turn off the stove and ready his lunch.
It happened again that evening.
Naruto sat up in a bed that was not his, wearing pajamas that were softer than anything he'd ever worn, and looked across the room into a face that was rounder, softer with big, white eyes staring back at him.
Hinata had thought she'd already gone to sleep, but suddenly she was standing shirtless under the glaring lights of a bathroom with a slightly molding ceiling, staring into the face of a blonde, blue-eyed, be-whiskered boy.
They watched each other in class the next day, at first flinching away and pretending it was an accident that they'd looked in that direction, but slowly realizing that it was no coincidence. Naruto gave a slow, solemn nod in her direction, and she gave an equally careful one back.
"Did it...happen to you, too?"
"...Yeah…"
"One second I was in my kitchen, and then I was - " he broke off, blinking, "Hey, why was that guy attacking you, anyway?"
"I was in the middle of a spar. What...did you do, while we were…?"
"I, uh, grabbed him and pulled him down. Sorry."
"Can you teach me?" she asked, nervous face suddenly stubborn.
"Uh...sure?" he scratched the back of his head, "I'm, uh, not really any good. I just do what feels right."
"You're better than m - "
And, without warning, they were once again staring at themselves, Hinata taking in her shy stature and Naruto gaping at the mud that had been on his cheek all day.
"Hey, I had dirt on my face! Why didn't you tell me?"
"W-Well - I…I didn't want to be rude…"
"It's not rude!"
Hinata got a strange shot of herself huffing and crossing her arms. "Your...your shirt's wrinkled, too."
"Huh? So?"
"...Well, it's unkempt. You should iron it."
"Huuuh? I don't even have an iron!"
And then they were back in their original bodies, Hinata sheepishly lowering her arms from the position they'd been in when he'd thrown them into the air. "I could lend you one."
"Really? Thanks! What's your name?"
"Hinata."
"I'm Naruto Uzumaki!"
…
…
A/N: Licentiosus Veneris loosely translates into Freaky Friday.