Use the mouth.

"Granny will kill me if she knows I used another way of entering her suit. Who am I? Pervy Sage?" said Naruto aloud.

With that he gathering up the suit and clothes and carried them over to an ally between two buildings. He began to strip his clothes to prepare himself to enter the suit. When he was finally done, he gulped in anticipation and held up the suit.

"Okay Granny, time to see what it's like to be you." he mused.

He stretched Tsunade's mouth to comically proportions in order to make room for his much larger body. Slowly he stuck his foot in, feeling around for the appropriate leg on the suit to fit his own in. Once he found the hole he slowly slide his whole leg in, bringing the mouth of the suit up to his knee. Confident, he dig his leg deeper into the suit's until the mouth was up all the way to his groin. Feeling around with his feet, he found five small openings and popped each of his toes into the little slots.

Naruto looked over the crumpled body of Tsunade at the foot in the suit. He wiggled the toes which displayed the bright pink nail polish Tsunade had applied.

"Neat!" yelled Naruto as he began to place his other foot inside.

His right foot slide into place more easier then his left, with both legs in place he pulled the suit up to his waist. From another standpoint it would look like a miniature Tsunade had gobbled up Naruto from the waist down. Chuckling, Naruto quickly stretched the suit up to his chest (with some difficultly) so that he hold place his arms in next.

The arms were a far smoother process then both legs combined. It was almost like putting in an over sized glove. Naruto finished fitting his arms inside and pulled up the suit all the way to his neck. He spotted a nearby mirror in the trash and flexed.

"Okay," He said to himself "now the final part. Good bye face."

Naruto pulled the bottom of Tsunade's jaw and aligned her bottom lip with his own. Holding the bottom half in place, he reached over for the Tsunade suit's nose and pulled it over his own. The suit's lips almost seemed to stick to his own as he had difficulty removing them. He looked over his own body. His chest, his face, even his gender had all been switched to Tsunade's. In fact he looked almost like a miniature flat chested Hokage. Admiring himself in the mirror. Naruto laughed.

"Well now what should I do with you Granny..."

Naruto twirled the pigtails of the Tsunade suit thinking of what what to do next. He spotted the air tank among Tsunade's clothes and hatched an idea.

"Oh right. The note said that if I breathe in Granny's air I'll actually become her completely."

Naruto gathered up the clothes and the air tank. The little dial on the valve read 1/4 full. Naruto became nervous. The note did say that he would be able to assume Tsunade's shape if he breathed the air in, but there was always the chance that he would end up just like here. A crumpled costume in a dark alleyway.

He finally decided it would be worth the gamble. He placed the clothing aside and brought the black air tank to his face.

"Well...here goes nothing." said he as he bit down on the valve.

Naruto turned the knob and immediately felt his cheeks puff out, much like Tsunade's did when she deflated.

"Oh crap!" He thought to himself as he prepared to face deflation.

But he did not hear the sound of suction coming from the tank as he did with Tsunade. In fact what he did hear was almost like the sound a balloon makes when being blown up by a helium tank. The air that was being **** into Naruto made it's way down his throat. It was soft air. The kind one would normally breathe in when on a warm day at the beach. There was also a slight scent of sake to remind Naruto that this was Tsunade's essence he was breathing in. The warmth of the air had made it's way down to his belly, where it slowly formed a soft budge as his stomach expanded outwards.

"Mmy Mm Mely! (Hey my belly!)" mumbled Naruto as his stomach neared a foot in length.

Naruto could sense what was happening here. All the air in the tank was making a home in his stomach. His belly blew to nearly two feet and still Naruto felt no pain. It was just like taking the deepest breathe he had ever taken. He gently rubbed his inflating middle as it quickly reached the three foot mark. He now looked like a tiny pregnant Tsunade.

Then something changed for a second as he touched his belly. He felt hollow almost, not just in his stomach but his hands, his legs, even his head (no pun intended). He felt almost like a pool toy eager to fill up the empty void inside of him to transform into a much bigger and grander form. There was then a quick sense of compression on his stomach, almost like someone was pushing in his inflated belly. As if someone had freed the air trapped in his stomach from imprisonment, the air of Tsunade spread outwards. Moving to fill the empty voids in his body.

Naruto watched his hands as his fingers were plumping up to fit Tsunade's size. Slowly his hands grew just a tad larger, he pressed them together and felt their warmth and softness as the air slithered like a snake up his arms. Another large pocket of air was traveling down his body. His toes grew to resemble little light bulbs until their feet followed suit, filling with the same warm air that his hands were. These weren't even the biggest changes as the air pressed upwards towards the more womanly body parts.

Naruto could feel his legs being pushed up as his view of the world slowly cranked higher. His calves and hamstrings were being blown to the busty female's proportions, he put his hands on his hip as he felt a strong resistance as they surged upwards. The butt was the last part of the lower body as it inflated to match his Tsunade legs.

His shoulders and stomach remained at the same size. Probably because there was nothing that expanded there on the female body. His arms had been long finished and he now felt the same super strength Tsunade had within. All the air slowly rised on his body and met in the center of his chest.

"Here it comes." Thought Naruto as he prepared for the giant expansion of his breasts.

But the air did not push out yet, and instead traveled further up to his face. His head grew bigger and his world grew smaller as the air expanded to met Tsunade's skull size. He could feel the largest activity being done on his lips, which were now plumped to the size of Tsunade's. When the process was complete Naruto reached to feel his now face but was stopped by the slight push in his upper body.

The most famous body part of the Fifth Hokage was now making it's show stopping appearance. His boyish chest now grew and grew from A to B to C, as it struggled to match Konoha's Leaders impressive bosom.

"Come on, come on..."mumbled Naruto as he tried to push all the air in his body to that one important point.

After much effort he finally heard two satisfying pops and his chest now displayed Tsunade's proud assents. From head to toe he was now completely the Lord Hokage. Naruto removed the air tank from his mouth and began to feel around his new shape to more sure this wasn't just a dream. As he stared down his body two massive globes of flesh were in his viewpoint.

"Wow..." He spoke in Tsunade's voice, to which he was not accustomed to and quickly covered his mouth.

With the air tank and the body of the leader of an entire village, Naruto could now do absolutely anything. An evil grin came across the Tsunade suit's face as the many ideas of experiments he could do with the tank came to mind.

"What shall I do...?"