Mastering Flying Raijin in just one lesson?

"Now I showed you how to make a seal. Now I'm going to show you how to activate it. When you activate a seal, you will enter a dimension where time doesn't move the same as hearing a second there can be minutes in this dimension, so you have enough time to decide which seal you'll go to this time but luckily you made your own seal and it will be easier now.

This is where people usually die, or worse, they didn't know this sealing formula designed by the Uzumaki clan it's a strong one and it used to be a prison or punishment it also drains your chakra but I fixed that issue with a few tweaks, but it still has a range problem but we'll fix that later, for now, try teleporting, but I have to warn you, your first time using space-time ninjutsu won't go smoothly with your stomach."

Ryuu nodded. Minato placed the other kunai a few feet away.

"You ready?" Ryuu nodded and disappeared from the spot, he felt something sucking him in but he also felt his surroundings fighting him, trying to push him out it was like bumping into many people at once but one thing is pulling him out and pushing the others away, then he came back to the training grounds with Minato standing where he left him.

"Well, are you ok? Did it work?" 

Ryuu nodded and gave him a thumbs-up before… 

"Blarrgh" Ryuu threw up everything he had for breakfast this morning.

"Yup, I expected that it's another problem with the Jutsu I hope to fix, hopefully." Minato didn't sound very confident in that "hopefully." 

"Anyway, I think I already found the problem with your flying Raijin." 

"Huh!" Ryuu's words shook Minato. He spent years learning the Jutsu and trying to perfect it, then Ryuu just started and he's already fixing his mistakes.

"Big brother, can I see your seal?" 

"Huh, my seal? What would you want with that?"

"I want to see something."

 Ryuu insisted, and Minato placed his seal on another scroll, then he gave it to Ryuu.

Ryuu looked at it with his Sharingan. "That's weird." 

It surprised Minato to hear this

After looking at it for a while,

He gave it back to Minato,

"I'm disappointed you haven't found out about your problem already. Big bro, you're dating an Uzumaki, and you didn't even tell her the real problem." 

Minato was stunned by what Ryuu said.

"The real problem?" Minato asked.

"You have the wrong sealing formula on this, instead of going for a stronger seal and wasting your time trying to strengthen your connection and smoother like Lord second, you both should've leaned in on your sensory abilities but also after my exceptional tip you should already be ahead of Lord second." 

Minato's eyes widened.

"Well then, tell me what it is." 

He said eagerly.

"Calm down Big bro it's not that simple, for this to work you would need to use your lightning affinity, this way you won't waste chakra and your reflexes would improve even further because of all the lightning chakra, this would strengthen the Jutsu to being an S-rank offensive ninjutsu."

Minato looked confused and shocked as he heard the problem.

"How did you figure this out so quickly? You've literally just started space and time techniques. How are you this good already?" 

He curiously asked

Ryuu slapped his forehead and said,

"Some genius you are." With a sarcastic tone.

Minato's self-esteem dropped because he had never been treated like this by a kid.

Minato's eyes widened as he realised what Ryuu was talking about. 

"I see. How could I have been so stupid?" 

Ryuu rolled his eyes and said. 

"Tell me about it." Minato Glared at Ryuu but didn't care about it.

"This could work, but doing this would be risky because it can kick you out of the dimension and end up dead, right?" 

Ryuu shook his head.

"Not really, because this formula works similarly to your previous one, but in this case it doesn't show you where to go it just protects you from being kicked out of the dimension and pulls you through, it's more like summoning Jutsu, only this time you're being summoned to a seal."

Seeing that Ryuu had thought about it already, Minato trusted Ryuu and went with the plan.

"Alright, I'll try mine first."

"Wait, Ryuu, you could die if this fails." Minato tried to stop Ryuu, but he had already made his seal.

"Oh relax, I told you I won't die until I achieve peace, plus the village will need the 4th Hokage more than me," Ryuu said as he smiled.

Minato wasn't sure about this new formula, but he was sure that if anyone could pull this off, it was Ryuu. 

"Alright, just be safe. What kind of Hokage would I be if I failed to keep my little brother safe, right?" 

It shocked Ryuu to hear Minato's words. And smiled back at him, then nodded.

They went back to where they started training the Flying Raijin. Minato sent a clone carrying Ryuu's Kunai with this new seal on it. After confirming that the clone had reached his house, he told Ryuu, and then he got ready.

"Alright, let's do this," Ryuu said before disappearing on the spot, leaving only a flash of yellow light.

"Interesting," Minato said.

Ryuu reached the other dimension and to his surprise he was there for only an instant he added his lightning chakra before teleporting and it majorly improved the speed it took for him to the seal he desired, fortunately there was only one, the one inside Minato's house.

He got pulled in with force and yet he still felt like he was in control, before he knew it he reached Minato's house and could see everything moving a little slower, even with his sharingan things are slower than before, he also didn't feel like throwing up. 

"Well, that's a good sign it worked."

He said as he looked around.

"Woah, it worked! It works! Finally!" Ryuu said as he jumped up in excitement, then snapped out of it. He looked for something to take back to Minato to show proof and he found some pretty weird things in Minato's room.

"Is that big sis kushina's?" He said as he saw Kushina's panties on the floor.

"You know what? I don't want to know what they did in this room." 

He said as he glanced away.

He kept looking until he found an old picture of Kushina and Minato on the side of his bed. He took it with him and put it in his bag, and disappeared back to the training ground in a yellow flash of light.

"Ryuu? You made it!" Minato said excitedly.

As Ryuu came back from his home.

"Well, are you ok? Did it work? Did you make it?" 

"Easy on the questions, Big bro. I'm the one who should ask questions here." 

He said that as he remembered Kushina's panties on the floor. 

"What is it Ryuu?" Minato curiously asked.

"I said I'm the one asking questions!, but that one doesn't matter now. Check it out." He said as he pulled the picture out of his bag.

It was perfectly fine. The same couldn't be said about Minato. He was staring at the picture and didn't blink once.

"Hey Big bro, are you ok?" Ryuu asked

Minato still didn't blink, then suddenly he started laughing. "Hahaha" Ryuu was confused and slightly worried and terrified about what was going on.

"Have you gone senile?" 

Minato wiped his tears and stopped laughing.

"Sorry Ryuu, it's just that I find it funny how I spent all these years trying to perfect this Jutsu, then you come along, and not only do you learn the jutsu on your first try but you also perfect it all in a day's work, isn't that funny?" He asked.

"Yes, that is a little funny now that I think about it." Ryuu shyly said, as he scratched the back of his head.

"Anyway, let's go share this news with the rest." Minato said.

And we packed all of our things and left the training grounds to go looking for the others…

We found Kushina and Kakashi near the market. Kakashi was being forced to carry all of Kushina's things. According to Kushina, that was "training." Kakashi.

Minato and Ryuu slapped their faces and sighed.

"Kushina, I have great news to tell you, but let's wait till we're all together, then I'll tell you." Kushina looked excited to hear this news, and she pleaded and begged for him to tell her.

"Thanks for saving me from this Ryuu." Kakashi looked relieved that Minato and Ryuu came by to save him from Kushina.

"Oh, no you don't! You don't rest until we're through!" He got pulled back by the hand and started panicking and tried to run and I could see tears in his eyes, but all the effort was helpless. He wasn't going anywhere.

"Ryuu, help!"

Ryuu turned a blind eye cause he didn't want to get caught up with this so he just said.

"You're doing great, Kakashi, keep up the good work." And he pointed his thumbs up.

"Poor guy," Minato and Ryuu said.

"Now let's go find Jiraiya-sensei." 

Ryuu pulled Minato back and said.

"No need. I've already found him. I'll go get him." Ryuu knew exactly where he would be, plus he felt his chakra close by.