The three genins tried to hide again but once Kakashi employed some unconventional methods he learned during his stay in ANBU, even the ingenious cloaking seals Naruto made couldn't prevent him from finding them. Alas, Naruto simply didn't have enough experience to configure the seal against every possible way of tracking somebody.
That's how the unfortunate Naruto, and yes, Kakashi targeted him first on purpose despite Uchiha or Hyuuga being better targets, suddenly found himself being pulled down into the ground, causing Hinata's eyes to widen as she inwardly scolded herself for not looking underground with her Byakugan while jumping towards him in an attempt to help.
Naruto wasn't in the best mental state when the attack happened. He was nervous and anxious. He just experienced the mental torture of being surrounded by thousands of bowls of ramen and not being able to eat any of it! He also knew he probably... maybe... most likely... went a bit too far with his dog-prank on Kakashi. As his mind was preoccupied with these thoughts, he wasn't able to react in time when Kakashi suddenly attacked.
Hinata was about to reach him when Naruto's body was fully submerged underground, only his head sticking out. Unfortunately for her, she was mid-jump when Kakashi sprang up from the ground and swiftly grabbed her by forearms and swung their bodies to the right, spinning on his heel as he threw her like a sack of potatoes right at Sasuke who was leaping into the fray from the opposite side.
Hinata's body crashed into Sasuke's for the second time that day, sending them tumbling through the air. This time, she was more prepared and Sasuke found himself quite literally being kicked out of his stupor when Hinata's feet brutally impacted his gut, making his body bend as she kicked him away from herself.
Not a second later, a fireball sent at her from Kakashi's direction engulfed her body... before its spinning rapidly increased more and more until it spun so fast the flames were extinguished, revealing Hinata's Kaiten.
As Sasuke's body flew through the air, he made use of the momentum Hinata's kick granted him to shift into a good position before he threw a shuriken at Kakashi who just finished casting fireball and was about to focus back on Naruto. This shuriken made him lean back and momentarily stop paying attention to Naruto which interrupted his attack on the defenseless prankster.
Nevertheless, Kakashi's left foot sprang forward while his body was leaning back, delivering a nasty kick to Naruto's chin with the intention of knocking him out... and breaking his jaw.
Much to Kakashi's surprise, as his kick connected, Naruto burst into smoke, revealing it was just a clone.
Naruto was quite proficient at getting out of body restrictions. He kinda had to be since he lived with Anko. All he needed was Kakashi being distracted for a second so he could replace himself without alerting the jonin. Fortunately for him, Sasuke's shuriken gave him such a distraction.
Kakashi wasn't surprised for more than a split of a second before his hand sneaked into his pouch and three shurikens found themselves flying in three different directions.
Hinata just finished her Kaiten, a bit disoriented because Kaiten was not made to be used mid-air. Her feet barely landed on the ground and she was intending to jump back into the fray when her eyes widened... She quickly threw her body back, evading the shuriken that aimed at her jugular by a half-inch. Unfortunately for her, behind her was a tree and her back impacted it with all of her weight, making her groan as she fell on her knees which distracted her from her intention of attacking Kakashi. She wondered how experienced her jonin-sensei must be to make such perfect use of the biggest weakness of Kaiten.
Not many knew but it took a split second for Hyuuga to reorient himself after finishing Kaiten. During that split second, they might as well be blind to the world despite their Byakugan since everything is just spinning in front of their eyes. That's why Hinata noticed the shuriken so late.
The second shuriken headed straight at Sasuke who was in the middle of weaving seals for the Great Fireball Technique. Sasuke's eyes also widened when he realized he can either finish the technique and get hit by the shuriken or interrupt his technique and evade. The Uchiha briefly wondered if his attack was worth getting hit by the shuriken but then decided there was no guarantee his fireball would actually hit Kakashi so he promptly threw himself into the roll to the left, fully intending to start quickly attacking again in order to minimize the amount of time Kakashi had without being pressurized.
As for the third shuriken... Naruto who suddenly leaped out of the treetops a bit right above Kakashi only barely managed to tilt his head downward, almost pressing his cheek to his shoulder. This allowed him to use said cheek as a shield. Instead of ripping through his neck, the shuriken whizzed through his cheek, leaving a bloody gash behind.
Naruto didn't pay much attention to his injury. Because he didn't dodge, he was still mid-leap at Kakashi and he fully intended to continue his attack.
Kakashi, as if momentarily stunned that Naruto didn't evade, also failed to dodge when Naruto's fist impacted his cheek.
Naruto wasn't happy though. The Kakashi he hit was too hard... before he could finish that thought, the Kakashi turned to stone, revealing it was just an Earth Clone. Naruto's breath briefly hitched as he remembered a small problem. Since he didn't burst into smoke upon hitting the earth clone, it practically revealed that he was the original. He was about to do a quick Kawarimi when...
"Secret Ninja Technique: Thousand Years of Pain!"
Naruto felt something enter his ass from below, sending a weak current of raiton chakra through his body, causing his eyes to bulge out before he was propelled forward, back into the treetops where he smacked his head on a thick branch with a loud crack just at the right angle which made his body twirl around the branch and start crashing to the ground. Naruto was out cold before he impacted the ground, breaking several bones, and started twitching.
Sasuke and Hinata finally reoriented themselves just in time to witness this historical moment, making them both stupefied while a chill went up to their spines as they subconsciously tightened their butt cheeks before giving Kakashi wary looks.
In return, he only eye-smiled at them before bursting into smoke.
Both Sasuke and Hinata cursed, raising their guard...
Sasuke suddenly raised his forearm, blocking Kakashi only thanks to being able to see him with his matured Sharingan. Unfortunately for him, a loud crack resounded through the surroundings, making him grit his teeth and soldier through the pain as Kakashi was already mid-kick towards his left side. Sasuke had no other choice than to lift his left leg, blocking Kakashi's kick with his shin... another cracking sound reverberated through the clearing when Hinata finally reached her teammate.
Kakashi refocused on the Hyuuga heiress, finished with the Uchiha who helplessly flopped onto the ground whimpering and trying to stifle his groans of pain. This lesson was, in Kakashi's opinion, very necessary for the kid. This would hammer down the fact that just because he can see the attack, doesn't mean he can react or safely block it.
Hinata pushed down her fear as Kakashi turned towards her and was about to attack when the alarm bell announced the end of this exercise. Hinata stopped in her tracks and blinked... her mind freaking out as she suddenly realized Kakashi's fist was just an inch from her face. Gulping, she bonelessly fell onto her bum, looking at the jonin with wide eyes. She didn't see him move at all!
Kakashi sighed and turned to Hinata, "Maa~, basically... unlike Sharingan, Byakugan doesn't give you a better perception. You can see a lot further than Uchiha can and with a bigger detail but that doesn't mean you can react or even notice someone moving too fast for your eyes. Or at least... that's what I was about to beat into you." He nonchalantly shrugged after verbally narrating her lesson, "Lucky you."
Hearing him, Hinata fainted, the mild chakra exhaustion finally catching up to her. It might not have seemed like it but during these few hours, it was her who used most chakra as she had to constantly keep Byakugan up while also using Kaiten multiple times.
Seeing that the fight was done, Anko jumped down from the treetops from where she witnessed the entire thing.
"I see you took your teaching duties seriously." She sweetly smiled, making Kakashi take a step back.
"You can say that." He casually replied, thankful that his forehead hid the bead of sweat rolling down his forehead.
"But Kakashi..." Anko cracked her knuckles with a wide ominous smile spreading across her lips, "What did we say about getting too serious against our cute little genins?"
Kakashi's eyes flickered towards the three kids who were either on the verge of chakra exhaustion or had multiple broken bones... 'Oh... Shit!'
Needless to say, he attempted to run for his life.