There comes a time where we all must grow old. When that time comes, it's important not to forget the lessons of our childhood. Because our childhood is the greatest training one can ever have.

~Sensei Wu, Ninjago

Mikey got very fidgety when he didn't have anything to do. Kind of dangerous too, unless you knew if you were going to be the target of his remedy for boredom. It was daytime, which meant they were stuck in the lair with not much else to do except for doing what they did to pass the time.

Michelangelo eyed his target. Donnie was in his lab, Raph was in his room. The latter was going to be a very bad option for this, especially if confined to his room. Donnie had told Mikey to keep out. So that left Leo, watching his Space Heroes show.

The young mutant turtle had trained so hard to accomplish this. This was his big moment. It wasn't often he could peg Leo with any prank that involved sneaking up. Now Mikey could've done this prank by putting it over Leo's bedroom door, but Mikey didn't feel very patient right now, and Leo was very, very touchy about the condition of his room.

Slowly, the orange-clad turtle snuck up on his oldest brother, who was fully engrossed in his TV show. He was getting closer… Closer…

The pages in a magazine left on the floor rustled as he stepped on it.

"Mikey." Just his name, but Leo put a very clear warning there.

Mikey groaned in disappointment, sitting down next to him heavily. Leo peered into the bucket on his lap. "What were you gonna try to do, drown me?" He picked up one of the water balloons, before placing it gingerly back into the bucket.

"Yeah," Mikey said in disappointment, not really processing all of what Leo had said. Leo gave him a weird look, before turning back to the TV.

After a minute or so of silence, Mikey set the bucket aside, and turned to his brother. "Hey Leo, it's been a couple years… Are you ticklish?"

The question caught Leo off guard. "What?"

"I am going to conduct an experiment," Mikey said seriously. He ran his fingers down Leo's arm.

Leo let out a short yelp, moving away. "Don't do that."

A very evil grin spread over Mikey's face, and Leo's eyes widened. Before he could protest, Mikey was on him, digging his fingers into Leo's neck, arms, and anywhere that wasn't protected by his shell.

"M-Mikey, stoppit!" Leo shouted in between laughs. He tried to push Mikey off him, but he was laughing too hard to be putting any real effort into it.

"Never!" Mikey said defiantly, still grinning. The tickling became more intense, and Leo shouted with laughter.

"Mikey, sto-op! Stop! Stoppit! Mikey!" In a desperate attempt, Leo seized Mikey by the wrist and started to tickle him under the armpit.

"Noooo!" Mikey screamed in protest, laughing as Leo was eventually the one on top of him. "Leo, no! No, no, no, no! Leo!"

"No mercy, right back at ya!" Leo said, still laughing.

"L-Leo!" Mikey's arms flailed helplessly, but he managed to get Leo in the back of the neck, and the tables were re-turned. "No mercy?" Mikey declared. "You ain't seen no mercy yet!"

"What the heck's happening?" Raph shouted, stepping into the pit room. With Mikey just in that moment distracted, Leo took the opportunity to escape. Pushing his youngest brother off him, Leo attempted to scramble to safety.

"No!" Mikey protested, starting to pick himself up. "Raph, catch him!"

Leo was just about to run past his red-clad brother, when Raph's hand snapped out and seized him by the arm. Raph was smirking back at Mikey, who raced over, laughing.

"No, stop!" Leo struggled uselessly, still laughing way too hard to be back to his full strength. "Raph, you're really awesome, and I'll tell you that more often if you let me go!"

"Not a chance," Raph replied, still smirking as he and Mikey dragged Leo back to the pit.

"HELP! DONNIE!"

The prodigy turtle looked up sharply from his work as Leo's cries broke through the lab doors. Jumping up, Donnie ran outside.

Being assaulted by both Mikey and Raph, Leo didn't stand a chance. He was running out of breath to laugh, and he spied Donnie, who was staring at them uncomprehendingly. "Donnie, help me!" he begged. "Mikey, no-! Stoppit!"

Putting as much effort as he could into it, Leo crawled out of his brothers' grasps, and took a deep breath, trying to crawl out of the pit, still shaking with laughter. Getting to his feet, Leo got out of the pit, only to have his feet swept from under him. He looked up to see Donnie holding his bō staff, grinning widely.

"Traitor!" Leo scrambled for refuge towards the pool, only for Raph to seize his ankle, and pull him back. Leo clawed at the ground, like someone in a horror film being dragged into darkness.

"I got him!" Raph said, pinning Leo's shoulders.

"No!"

"Attack!" Mikey and Donnie descended on the helpless blue-clad turtle.

"NO!"

Splinter had been in a deep meditative state, when something suddenly broke through the stately walls. Having keen hearing as a rat sometimes had its disadvantages.

"Help! HAHAHAHAHA! N-no, D-Donnie!"

"Don't let him go!"

"Let me go!"

"Sorry, Leo! But Mikey's making the rules this time! Get his feet!"

"NO!"

Eyes narrowing, ear flattening, Splinter got up, and exited the dojo, meaning to admonish his sons and tell them to use their 'inside voices'. But he paused when he saw the scene. Leonardo was flailing underneath his brothers, his laughter becoming so intense Splinter could hardly hear it, all the while begging for mercy. Raphael held his older brother down, shouting suggestions, while Donatello tickled Leonardo's arms, at the same time trying to avoid injury as they flailed about. Michelangelo was just avoiding being kicked in the face as he tickled the underside of Leonardo's feet.

Splinter found himself smiling, despite the sternness he'd had only a minute ago. What with all his sons had been going through only these past few months, it was so nice to see them revert back to the games of their pre-teenhood.

"Raph, hold his arms!" said Mikey.

Leo gasped for air, still laughing as Raph pinned his wrists. "No! Ple-ease, no!"

"Say 'Mikey is way more awesome than me'!" Mikey tickled Leo's shoulders, and the oldest turtle let out a shout.

"Mikey is more awesome than me!"

"Say that I'm the best in the team!" Donnie threw in his two cents.

"Donnie, you're the best in the team! Let me go!"

"Now say that I am your superior in every single way!" Raph included.

"Raph is my superior in every single way! Now let me go!"

"NEVER!"

Leo let out a cry of despair as his brothers continued on relentlessly. He spied Splinter standing on the ledge above them. "S-Sensei, save me!" He sucked in a deep, laughing breath. "I can't breathe!"

Splinter himself was on the verge of laughing, but he decided to spare his eldest son from further torture. "Alright, that is enough."

Seeing their Sensei, the younger turtles quickly released their leader, who curled up, shaking a little from the laughter. "Oh man, I will so get you guys back," Leo vowed breathlessly.

The other turtles, a little breathless themselves, laughed. "I'd like to see you try," Raph retorted, grinning. He abruptly released a girly yelp as Master Splinter, having quietly made his way down to his sons, gently tickled him in the neck.

By a childhood instinct that had died out by twelve years old, the other three turtles scrambled away to safety. Raph tried to make his escape, but Splinter caught him by the back of his shell. "Just remember, my sons," Splinter said, smiling. "No matter how old you get, no matter how skilled you are, I will always win out in your childhood games."

Leo stumbled to his room, completely exhausted from the games of that afternoon, and the patrol that night. He smiled. They hadn't played with Master Splinter since they were ten or so. It was good to know that they didn't always have to be as mature as they were meant to be.

Yawning, the blue clad turtle opened his bedroom door.

SPLASH.

"MIKEY!"

A/N HardyGal: Very first completed one-shot. The quote on top is from another epic ninja show, Ninjago, and I don't own it, same as I don't own TMNT. If I did, I'd make Leo go through at least one small tickle session.