Naruto walked merrily through the village on the way to the Hokage's tower. He could NOT believe it; And S Rank mission, his very first one ever! A part of him was skeptical of this seeing as how, was still a genin, and 2. It was given by Grandma Tsunade.

The buxom Hokage had a habit of hyping him up for certain missions, only for him to eventually find out that it was all a load of crap just to dump some dumb assignment on him. Most recently, getting saddled with the horrible task of border line babysitting her rich friend's little brat.

But Naruto decided to remain open-minded to this whole thing, maybe this time Grandma Tsunade would cut all the games and finally deliver, but he wasn't gonna make any promises to get the job done until he knew what he was getting into.

Making his way finally to the tower, he knocked on Tsunade's door.

"Come in! Ah, Naruto, you finally made it." Tsunade greeted with a smile.

"Mornin' Grandma, so what's this super serious S Rank mission you got for me?! Is it legit?" Naruto asked.

Tsunade's eye twitched at hearing that accursed nickname, but suppressed the urge to lock the whiskered boy in a noogie. She was about to do away with that nickname soon anyway.

"Well Naruto, it's not a mission where you'll be leaving the village or anything like that, that's still out of your league for now, but rather you'll be heling me with an experiment that IS and S Rank secret. You having an extremely large amount of chakra makes you the perfect partner for it." Tsunade explained.

"Hmm…okay. But is it gonna hurt?" He asked.

"There's a chance it will and a chance that it won't, but the pain shouldn't be all that intense, you might just feel some pressure."

"Okay, so when do we start?" Asked Naruto.

"We can start right now. But first…" Tsunade got up and walked near the door and made a few hand signs and then pressed her hand against it.

"Since this is a secret mission, it needs to be hidden, so I applied a seal along with a sound barrier to the room."

"O-Okay." Naruto nervously answered.

Tsunade took notice of this sudden change in the boy's demeanor and put a reassuring hand on his cheek and guided his face so he could look at her.

"It'll be fine, alright? I'll be here to guide you the whole time."

"O-Okay…" Naruto said with a slight blush.

Tsunade had to fight to keep herself from giggling, he was just so cute.

"Okay Naruto, first I need you to take off all of your clothes," Said Tsunade.

"WHAT?! I CAN'T GET NAKED IN FRONT OF YOU!" Exclaimed the blonde genin.

"And why not?" Asked Tsunade with an amused smirk.

"You're a girl!"

"And?"

"AND?!"

"Listen brat, you don't have anything I haven't seen already. I've delivered babies, and given full medical exams to both men and women. So what's the problem? Or are you chickening out your first S Rank mission?" Tsunade asked in a mocking tone. She knew she could bait him in with a bit of teasing like that.

After a long pause that consisted of Naruto mimicking the actions of his close friend Hinata, Naruto slowly began to peel off his jacket, then his shirt, then his shoes, and finally his pants.

Tsunade rolled her eyes.

"ALL of your clothes brat!"

"Okay! Okay!"

Slowly, Naruto lowered his boxers until they were around his ankles, and then they were off, and kicked to the side along with the rest of his clothes. He stood there in front of her, naked as the day he was born, eyes to the floor and his hands desperately trying to cover his….little friend.

Tsunade's eyes nearly bugged out of her head when she saw Naruto's member, this brat was HUGE! Before selecting him for this "mission" she theorized that the Nine Tails would enhance his size but not to the point where she'd wonder if he could lean on it if he ever got tired. She guessed that it was about 11 inches long and about 2 inches thick. Nothing she couldn't handle, but still!

After wiping a bit of drool from her lip, Tsunade brought her thoughts back to the task at hand. She still took the time to scan the rest of him. He seemed to be possessing some developing muscle, but not much. He was a bit scrawny, with clear signs of malnutrition. She would have to fix that. But first…..

"Alright Naruto, it's my turn." Tsunade said happily.

"W-What?!" Exclaimed the extremely red-faced blonde.

She began to undress, first removing her trademark jacket.

"Well of course, I need to be naked for this experiment too. Is that a problem?" She teasingly asked bending down slightly to look him in the eyes.

"N-No….its fine." Naruto said as he quickly averted his eyes back to his feet.

Letting out an amused chuckle, Tsunade kicked off her high heels to the side, then gripped the sides of her pants and slowly lowered them off her body, it helped that she chose not to wear panties for this, and finally she gripped the open front of her grey shirt and pulled it apart, allowing her large breasts freedom.

Naruto in his moment of curiosity peeked up just for a second and caught a glimpse of her legendary mounds and then looked back down before he thought she'd notice. He remembered that Pervy Sage went on and on about them several months back when they were still looking for her, but from what Naruto saw, they were even bigger than he described them. They had to each be bigger than the boy's head. No wonder he didn't see a bra on the floor.

Truth be told, he not only took in her breast in that brief moment, but her entire front. His "Granny" had a glorious, thick and curvy body. Her legs were slender and athletic, her thighs were thick and strong, her stomach was toned with, and her body just seemed to look fresh, as if she oiled up before coming to her office.

"Like what you see brat?"

Naruto was snapped out of his thoughts by her voice and went back to succumbing to his extreme shyness.

"I just….I….I mean…I'm…sorry….."

Tsunade couldn't suppress her snicker, "Calm down Naruto, you were bound to see me like this for the experiment anyway, right?"

"R-Right…" Naruto nervously said as he looked up slightly, trying to desperately to focus his sight on her eyes.

"Good, now for the next step…"

Tsunade began to form various hand signs that Naruto didn't recognize and finally clapped her hands together.

What happened next nearly gave Naruto a heart attack.

Tsunade's body began to tremble and soon it looked like she was beginning to grow taller to about 7 feet, her arms began to expand, her biceps growing, her thighs that were already thick were now even more muscular as well. Her legendary breasts that were already revered and praised (in secret of course) grew to the point where their thickness and size made watermelons feel jealous. All in all, her body resembled that of a female body-builder. An extremely busty and curvy body-builder.

Needless to say, Naruto was stunned, his mouth open, his face once again a deep shade of red, and now sporting a cock that was twitching and throbbing. He didn't know whether to be scared or aroused so it would be hard to tell just by judging his member's current state.

"Now Naruto, this jutsu is quite useful in battle, as you could probably guess, but it's very draining to one's chakra. In my current state, I can only keep it going for maybe an hour, but that's where you come in. You have enough chakra to share with me in order to truly test this technique. This experiment is to confirm if there is a more…..fun way for ninja to share chakra with one another. Do you understand?" Tsunade asked with a smile, which soon turned into a confused look as she saw that the genin in front of her was still frozen in place with his mouth agape.

After waving her hand in his face for a minute and getting no response, Tsunade let out a sigh and turned around to her desk, giving Naruto his first view of her thick, built butt, and then in one quick motion pushed all of the scrolls, papers, and other supplies off and turned back to Naruto.

Naruto was taken out of his trance when he felt two long-strong arms wrap around his torso and lift him up. Before he could react, Tsunade closed the distance between their faces, capturing his lips with her own. He tried to wiggle out due to sheer shock but soon found it impossible after he felt an extremely strong hand cup the back of his head. His heart raced faster and faster as he felt Tsunade deepen the kiss, keeping him there with her firm grasp. She began to lightly peck and at his lips and trail kisses up and down his cheeks and neck before claiming his lips again, this time with an open mouth, flicking and sliding her tongue on his lips. Soon she was able to force her tongue through his lips and into his mouth, sliding all around his mouth and on his tongue. Tsunade then turned around with Naruto still in her arms and leaned on the desk, her body keeping the whiskered youth down as she continued to have her way with his lips. Tsunade could feel his member rubbing against her stomach. She felt it throb and twitch with excitement and felt herself getting wet herself at the thought of it being inside her. With one last lick to Naruto's tongue, Tsunade released her lips' hold on him.

She still had Naruto in her arms, his head tilted back as he gasped for air.

"Hm….not bad brat, but you still need time to get used to this body."

"H-How am I gonna do tha-MMPH!"

Naruto never got to finish that question as Tsunade let her grip on him slip to where his head was lined up with her gigantic bosom. With her new more powerful arms wrapped around his neck, Naruto suddenly found himself buried between Tsunade's enhanced breasts. Each breast surrounding his head and resting on his shoulders.

Naruto had to stop himself from dying of shock for a second, this was almost too much for him. He recalled one time that he rounded a corner too quickly and came face-first with Tsuande's cleavage. He was able to come out of the whole ordeal unscathed with only a mild blush and unmerciful teasing from Tsunade but that was about it. This was entirely different, she was intentionally forcing his face to her bust. He was currently living Pervy Sage's dream!

"Hey brat, you still alive in there?" Tsunade playfully asked with a giggle.

In response she got a muffled, "Mmhmm….."

"Well then get ready, I'm about to make you ready to release you chakra."

Naruto didn't know what she meant but suddenly heard the sound of her foot being place on her desk. And then suddenly felt himself seated on her muscular thigh.

"Let's see how hard you can get Naruto." Tsunade purred.

She kept her grip on Naruto, keeping his head tucked between her breasts as she grinded him on her thigh. Back and forth his lower body went, his erect member sliding along Tsunade's powerful thigh.

"You like that brat? Knew Jiraiya had to have rubbed off on you a bit but I didn't know it was this bad?" Tsunade teased.

Rather than a muffled protest, Tsunade heard a whimper from the valley of her bosom. Still she continued to grind Naruto against her, feeling his cock throb from the sensation of his sliding along her skin. Soon the whimpers became moans that seemed to get louder and louder.

"G-Gran-"

"No. If we're going to keep doing this, you're to call me Mistress Tsunade or I'll stop right now and the mission will be a failure." Tsuande said sternly.

"M-Mistress….something's coming…." Naruto struggled to say.

"Looks like you've reached your limit for this round…fine." Tsunade then lightly tossed him upward and caught him, with his legs on her shoulders, she held in a positon fit for a power bomb, but took his cock in her mouth, or at least she took what she could in her mouth. With one hard suck Naruto released his load in her mouth. Tsunade sucked to hard that not a single drop of his cum leaked out, she had gulped down the entire load. She released his member from her lips with and laid Naruto onto her desk.

"Mmmm….. That tasted alright brat. I can feel chakra coursing through me right now…" Tsuande said with a satisfied smirk. He was all hers now.

"Th-That was…great…." Naruto said through panted breathes.

"And it looks like you're still hard after all that. Impressive. Now it's time for the next part of the experiment." Said Tsunade as she put one foot on the desk again, giving him a view of her womanhood.

"Before we can get to that next stage, you need to stimulate this area of my body." Tsunade said, motioning his gaze to her pussy.

"First, use two fingers to get it ready"

"Y-Yes Gr-I mean Mistress." Naruto said as he slowly took his index and middle finger and gently touched the outside of her womanhood, earning gentle moan from Tsunade.

"Mmmmm…y-yes Naruto, put them in deeper." Tsunade moaned out.

Naruto did as he was told and thrust his fingers knuckle-deep into her pussy, he felt her walls tighten around his fingers as her mound became louder. He felt around the inside of it with his fingers, making Tsunade even more wet with every second, every twist and turn of his fingers. He felt her juices leak out and eventually flood out of her with a pleasure-filled scream. Soon Naruto got an idea and began thrusting his fingers in and out of her womanhood. Tsuande began to moan louder and louder, and eventually Naruto was mesmerized enough by the fragrance of her pussy and took his fingers out, only to brush her intimate lips with his tongue. The clear height difference made it easy. Tsunade was currently on Cloud 9, getting wetter and wetter with every second of Naruto licking her pussy. She felt that she was losing control of herself and to her surprise she suddenly came, her juices flooding all over Naruto's face.

While she was filled with pleasure she was also frustrated. How could she allow some snot-nosed virgin genin to make her cum like that?! She looked down to see Naruto still helping himself to her pussy. Just who did he think he was?! With one quick motion, she took hold of his wrists in each of her hands with her back to him.

"Get on your knees right now." Tsunade demanded in a rough tone.

"Okay M-Mistress." Naruto nervously obeyed, and soon all he could see was her built booty.

"So…what are we doi-MMPH!"

Naruto soon found him face-first in her ass, all he could see was her cheeks smothering his face as Tsunade held his wrists in place.

"You okay back there little Naruto?" Tsunade mockingly asked as she wiggled and shook her ass in his face.

"Mmmph! Mmmph!"

"Sorry, I can't seem to understand that! Maybe I need to sit down." Tsunade said as she walked backward behind her desk, planning herself in her chair with a satisfied sigh.

"Yes…much better…what about you Naruto?"

"Mmph! Mssstwsssss!"

"You want me to do what? Well I guess I can do that for you."

Tsunade lifted her ass off of Naruto's face, only to bring it down again, and then lifted it again, and then plopped it back down on his face again. She kept on doing this, bouncing her ass on his face rubbing and grinding her cheeks all over him.

Any other man or person period for that matter would've been dead. Luckily Naruto was not a normal person. Tsunade knew he could take this and even saw that this particular action fueled his "excitement."

"Seems you like being smothered by my ass cheeks almost as much as much my boobs. You really are more perverted than Jiraiya. But I guess that's my fault too huh?"

"Mmmph"

"Oh well, at least this is still ready for use." Tsunade said as she grabbed Naruto's cock with one hand and began to stroke it.

"This made you really excited didn't it? I knew I made the right choice choosing you." Tsunade said as she increased the speed of her strokes, using the other hand to play with his balls.

Naruto let out muffled moans and screams in Tsunade's ass as she continued to pleasure his cock. He couldn't believe this was happening, but wasn't upset about it at all. This was great! The only bad news was that that this meant he was perverted like Pervy Sage, but if that's the case, wasn't his Mistress also a pervert?

His thought were cut off as he felt himself reach his limit, his moans getting louder and quicker as did Tsunade's stroking and soon another flood of his cum came out. Tsunade, not wanting to waste a drop of his "chakra" aimed his cock into an empty sake bottle that she was then glad she didn't discard like the others. With another satisfied sigh she let go of his cock and leaned back in her chair and just sat there for a minute, but then realized what she was doing after she felt Naruto pat her thigh.

"Oh! Sorry Naruto." Tsunade said before standing back up, with Naruto's face still stuck between her ass cheeks and lightly pulled him out, holding him under the armpits in front of her. He gave her a weak smile that told her he was okay. She couldn't help but smile back and sat back down in her char and cradled him in her lap, one hand stroking his member again while the other cupped the back of his head as he decided to help himself to one of her breasts, suckling the nipple, earning himself some of her legendary breast milk. Tsunade remembered he never got the chance for this kind of bonding, what with his life basically being flipped the night he was born, so all she could was smile and caress his hair as she breast-fed him.

"That's it…drink up my little knucklehead," Tsunade cooed as she pushed him closer to her breast.

Naruto continued to suckle like a deprived baby until he finished and released her nipple from his mouth with a *POP*.

"Alright Naruto, you've done well so far, now it's time for the final part of the mission." Said Tsunade as she stood up with Naruto still in her arms and walked over to the bookshelf in her office. She pulled out one particular book and suddenly the entire bookshelf slid to the right, revealing a room, with a bed, a bathroom, and even a T.V.

"This is the private quarters Hokage get to use after late nights of work, it's perfect for the final part of the mission." Explained Tsunade to the blonde in her arms.

"Okay Mistress, I'll do my best!" Naruto said with energy.

Tsunade giggled at his usual determination and playfully tossed him on his back in the bed. She then crawled near him and placed and gentle kiss on his forehead, just like the one he got from her when she gave him her necklace. Naruto felt a warm feeling spread across his chest at the memory, but soon was pulled back to reality after he felt Tsunade positioning his member into her intimate lips, she finally got it perfect and let herself drop down onto it with a loud scream. Naruto let out his own pleasure-filled scream as well, it was even better than her mouth, it was so tight inside her, yet so slipper too. Tsunade's new muscular body was quite heavy, but felt so good. Tsunade bounced wildly on Naruto's cock as best as she could, it was stretching her womanhood with its girth to be honest, it was almost difficult to say the least, but felt so good to her. The bed creaked and squeaked at the pressure of having Tsunade moving up and down on Naruto. Naruto could feel her ass bounce off his legs from her sat up position on his cock. Ina bold move he sat up, thrusting his head between her breasts again, and grabbing two handfuls of her ass cheeks. He squeezed and rubbed the built rear end, earning louder moans from Tsunade as he rubbed his face all round her cleavage.

"Oh! N-Naruto…..yes…! Enjoy my body! Pleasure yourself with it!" Tsunade screamed.

"M-mistress! Your pussy…it…the best!" Naruto squeaked out from within her bosom.

"AH! AH! AH! AH! AH! YES! I CAN FEEL YOUR COCK SWELLIGN UP! FILL ME WITH YOUR CHAKRA!

"HERE IT COMES MISTRESS! TAKE IT ALL! IT'S ALL YOURS!"

"AHHHHHHHH!" Tsunade yelled as she felt Naruto's entire load release within her walls. She took hold of him again lied on her back with him still inside her, making sure that the entire load shot into her pussy.

After one more squirt inside her, Naruto looked up from her bosom, "M-Mistress…..is that enough chakra for you?"

"Yes…*pant* Naruto…you did excellent." Said Tsunade.

"That's great…." Said Naruto before snuggling deeper into her breast and falling asleep.

Tsunade smiled down at him and ruffled his hair.

"That's my little knucklehead…."

THE END