I don't own. This will be the basis for this story line of Mistaken Gender…although I probably need a better name as some pairing won't be mistaken gender…

Tsuna's usual gang that he walked home with had left without him, and they each felt like crap. Hibari had ordered Tsuna to see him after school…alone. And Tsuna agreed. All the way home all Yamamoto heard was Gokudera's whining about leaving "Decimo with that bastard Hibari". fortunately for Tsuna, this was a planed out thing that he really enjoyed.

Things played out very differently behind closed doors. Tsuna walked into the disciplinary committee's room with a small smile. Hibari sat behind the large oak desk and snorted as the herbivore stepped into the room. Hibird flew out of the window to enjoy the perfect summer day. Tsuna closed the door and locked it. His smile grew as Hibari's did.

If someone had been listening in the empty school they would have heard a girl moan in delight. "Tell them" commanded the girl "I can't take the hiding"

The other voice laughed "I think this game's going to be very interesting" followed by another moan from the girl.

Tsuna got back with a flush on his cheeks and a very spaced out look on his face. Reborn dropkicked the boy to the floor "your late get to work" and amazingly the boy got up and did, without complaint. He did his work within an hour and was soon in bed.

The next morning Tsuna followed his normal routine and walked with all the guardians except Hibari. Who was waiting at the gate. Tsuna's smile grew larger as Hibari snarled. Everyone but Tsuna froze. This snarl was crueler than normal. Tsuna kept walking towards the head disciplinarian until Hibari gripped his shirt and kissed the young boss soundly. The group behind him felt their jaws touch the floor. Reborn smirked. Tsuna grabbed Hibari's hand and grinned " I guess I should tell you we're dating"

The crowd was still frozen until Gokudera screamed "YOU'RE GAY?!" (with just a pinch of hope)

Tsuna had a very confused look on his face "no, we're both straight"

Yamamoto laughed a confused chuckle, "but you're both guys…"

Tsuna grinned "wrong" the uncomprehending looks he got prompted him on further "one of us isn't a guy"

And the two love birds walked off with a bunch of Hibirds showering the way behind them with flowers.

Gokudera and Yamamoto were arguing, nothing unusual. However the content was very strange "Hibari's the woman"

"No way think about it for two seconds and it can't be him" who was arguing what was also strange. The silverhead was arguing that Tsuna was the girl. Gokudera glared a the baseball freak and sighed "when you met the boss you had an instinctive need to protect him right?" the other nodded "that's because he's a GIRL!"

Yamamoto shook his head "I had the same feeling when I met Lambo and I-pin" the two were about to tear each other's throat's out until a fedora wearing baby smacked both of them with a random paper fan. "You two stop. If you really want to know why not just do a panty raid?" Gokudera started praising the baby until Yamamoto broke in.

"Tsuna wouldn't be a problem but we don't even know where Hibari lives and if he found us…" both boys shuddered and could almost feel the phantom teeth bite into their skin.

Hana, Haru and Kyoko were wondering the same thing in a much calmer tone. "Haru was surprised about that…"

Kyoko giggled "I was too. But they make a good couple"

Hana butted in "who makes a good couple?"

Kyoko answered "Tsuna and Hibari"

Hana hissed "I knew it! I told you he was gay!'

Haru sighed "He isn't gay"

Hana "but their both guys!"

Kyoko "one of them isn't"

Hana "who?!"

Haru "we don't know"

Hana "They're lying"

Kyoko "I'm pretty sure not"

Hana thought about it and started drooling a little bit. Wiping her mouth with the back of her hand she sighed "I would love to see that" and the other girls looked on in confusion.

One of the subjects in question was asleep remembering the time he found out about the other's femininity. It had been a long day and he had accidentally bumped into the other after everyone had left. Chest to chest bump and his eyebrows flew into the stratosphere "are those breast?" the other crossed her arms over her chest. They had soon started taking more frequently and became closer and closer. He had started to notice the little things that gave her away until he could only see her as a girl, until she told in that she was in love with him.

Shortly after that they had made many impromptu visits to the committee room. None of these trip were for more than kissing. Not that either of them didn't want to take it to the next level but it would have been weird with it being under wraps and all.

The sleeper woke to a light brush on the lips from the lover. He stood up and grabbed her and they walked out of the school hand in hand. Many guys gagged and many girls drooled. That is until Gokudera told them one of them was a girl. Bets were being placed in less than a second.

The next day Gokudera and Yamamoto were over at Tsuna's after school trying to see any incriminating evidence. They tried to sneak a peek at the laundry but between the wind and Iemitsu's laundry they couldn't see a thing. They next tried going into Tsuna's room but were stopped by the monumental firestorm riled up by Reborn, I-pin, Lambo and Lambo's new obsession with C-4. They tried to go through the dirty laundry but the idea of Nana seeing them gave them pause.

They went with plan B. Go to Hibari's

They had found out the address of the cloud guardian that day after Reborn's idea and were now on the roof trying to find the room of the guardian. They dropped down from ropes until they spotted a dresser in a stark room. They gently pried open the sliding glass door and snuck over to the dresser. They opened the drawer and pulled out a set of worn white briefs. Gokudera grinned at Yamamoto who handed him the money as the winner spoke "I thought Hibari would have worn boxers…" then the owner of said briefs walked in. poor Tetsuya Kusakabe screamed as he saw two men in ski masks holding up his lucky underwear. Hibari busted into the room with tonfas coated in flame. The two ran out of the house faster than the cloud could catch them. Huh, amazing how fast you can run when your life is on the line.

The next day the duo was pulled out of class by Hibari and beaten severely. So badly in fact that both were dismissed from school. Tsuna found Hibari by the gates and greeted the boss by dragging out a kiss that left both panting. Ryohei looked at the two and asked "isn't it weird, I mean both of you look like guys…" and he twitched.

Tsuna laughed at the sun and spoke "you don't notice the little things like we do" and the group walked home.

He dreamed that night of the first kiss they shared. It was after they had spent four hours talking over ice cream. Hibari had gotten strawberry for Hibird and vanilla, and Tsuna had gotten mint chocolate chip. One of them suggested walking around and the pair eventually wound up at the school in the committee room, where most of their rendezvous took place. Hibird had long since flew off to sleep in it's owner's room. They had continued talking- both spoke about their doubts. While it didn't surprise Tsuna that Hibari had doubts the content of the doubts did. They had spoken until well after midnight. The woman was fearful about her femininity the man laughed and reassured her that in his eyes she was all she needed to be. She had kissed him. Then he grabbed her arm and kissed her again, deeper, more passionately. They kissed and kissed and kissed until she actually fell asleep standing. He had woken her and took her home. From that moment on both knew their relationship would never be the same.

Tsuna was getting ready for school when Reborn stepped on the head rest of the bed. He had repeatedly told the two to speed up the relationship. "Tsuna" the boss turned around "tonight all the other guardians, I-Pin, Bianchi, Nana, Fuuta and I are going to see your father in Italy. So you'll be alone. You might want to invite someone over…you know just as a precaution." and the hitman smirked as Tsuna grinned.

Tsuna had told Hibari the situation and the latter had dragged the former into a heated kiss. Several girls had taken a sudden interest in the pair over the past week and the two had gotten used to it.

After a long day the two were locked in a mouth war as the two busted into Tsuna's room. The man's back hit the bed as she straddled his hips and took off her shirt revealing a tight vest. He smirked "that's how you did it…" earning him a giggle. He reached up and took the top button in his mouth and slowly undid it before kissing the skin he had just unwrapped much like a gift. He suckled on the skin earning a moan from the woman on top of him.

She stuttered "s-s-stop" he didn't until she had a red mark where his ministrations had landed. She pouted "Why am I the only one getting undressed?" and he quickly peeled off his shirt and took the next button in his mouth. Her lips curled in a mischievous smile and she ground down with her hips causing both of them to gasp and writhe causing even more tremors as they moved against each other. Under much duress he finally managed to pop off the last button and was rewarded by being the first person to see the surprisingly large treasure he had unwrapped. She covered her chest self consciously. He grabbed her wrists and pulled her arms away before kissing her nipples earning him a slight whimper. She started to squirm as he continued to attack the sensitive areas. She responded by sliding her hand up his toned leg until she reached the hardening in his pants. She pushed him down and pulled off his remaining clothes as he pulled her pants off her surprisingly shapely form. She pushed him back onto the bed and grabbed her prize before pulling it into her mouth causing the man below her to groan and try to halt himself from pushing up and into her moist, soft, warm mouth. He pulled her head up before kissing her. He whispered into her ear between ragged breaths and kisses and she swung her hips over his face before returning to her treat. He slowly licked the lips in front of him causing the girl to tremble along with him. He pushed his tongue into her as she started bobbing her head up and down. As he felt his body start to slip he slowly inserted a finger deep inside her causing her to fall ahead of him. He smirked as she clenched down on his finger. She rolled off of him and gasped as he kissed her closed eyelids. As he started to pull away she grabbed his shoulders "nu-hu, not until I finish you off" he was about to protest until she wrapped his cock with her velvety lips. He didn't last much longer. She kissed her way back up to his mouth and they kissed more and more heatedly until she couldn't wait. She guided his hand back down to her warm core and he started his ministrations again. His fingers propelled her over the edge of sanity twice before he was ready for more. She noticed and tried to say something. She was cut short as he added a third finger and she started grinding against his hand. He shook his head with a sinister smile and pinned her hips down with his free hand. After hours of sweet torment he relented and let her jump on top of him as she pulled herself onto him. She gasped as she felt something delicate stretch inside her.

He gripped her shoulders "are you Oka-gwa!" as she impaled herself further down on him as she felt a glorious sensation deep in her belly. She pushed him hard that night. Neither could forget the simple act that had pulled them this deep in to it.

Two weeks later the entire school was waiting for the love Hibirds by the gate. Tsuna and Hibari both stopped at the sight of so many people. The student president stepped forward. He cleared his throat shakily "u-um, we the students have reached a conclusion" both Tsuna and Hibari smirked "we believe the woman is…" he took a deep breath and looked back at the entire student body and faculty. The question had bugged everyone, even the principal, for those weeks of mystery. "Tsuna" both laughed.

Tsuna stepped forward "Sorry, guys wrong" and the head perfect walked away with her boyfriend to see one Adelheid about finding something to make her seem feminine. As the two continued on Tsuna looked over his shoulder "why did you guys think I was the girl, you've seen me in dying will mode before.."

The student body, including the guardians, including Mukuro, stood in shock as Reborn fell off Yamamoto's shoulder from laughing at the faces they pulled.

Much money traded hands that day (most of it went to Reborn).

The next Monday was one nobody would ever forget. The Decimo family was gathered to greet the Ninth as he landed. Tsuna and a mystery woman met up with the other guardians. Gokudera felt a tinge of familiarity as he saw the woman but it faded quickly "Boss, who's the girl?"

She was a beauty to be sure. Her gentle curves had startled the three others. They weren't overly defined but they were undoubtedly feminine curves, however small. The black skirt she war dropped only an inch below her knees with a long slit that showed a dangerous amount of pale thigh. The dark red fitted button up shirt she wore cupped her breast and hugged her form in a way that spoke of sophistication and also of danger. Gokudera thought it would be like kissing a typhoon. Her black hair just shadowed her eyes to the side the family was on. Gokudera could see a small amount of lipstick in a shade matching the shirt and the same tone of make-up around her eyes.

Tsuna chuckled as a familiar growl cut through the air "call me a girl one more time and I'll bite you to death" and the family felt their jaws drop. Hibari couldn't be this gi-woman in front of them! He stared at her face. Those same iced over gray eyes. That same feral frown. Those same full, sensual lips-WHAT THE HELL? As Hibari glared at the others who were staring at her they started to notice those "little things" that Tsuna had mentioned. Who had seen those full lips or that pale unmarked porcelain skin? Gokudera shrugged hyper intuition had its perks after all. A phone rang out, Hibari growled and pulled the offending device out of her pocket. "Kyoya Hibari….Damn" and she rushed off.

She hadn't been gone a minute before the others closed in on Tsuna about to ask questions until…

…they opened their mouth…

…They took a breath…

…Their first squeaks issued forth…

Hibari came rushing around the corner and pulled her boss into a kiss that would have him needing a cold shower and her needing to find a few minutes alone with her tonfas (they're her weapons of choice for moments like this).

Hayato moved first after she left "who did you find out she was a girl?"

Tsuna laughed and shook his head "I was in the school late due to those make up test and I didn't realize how late it was. I started running and ran chest to chest with her. I felt something and asked. She dragged me aside and said that if I told anyone she knew places nobody would ever find the body…" he smiled and walked to greet the current head of the family.

The week that The Ninth was in town Tsuna didn't see his girlfriend much nor after they left until one day…

Tsuna had seen Enma sulking for the past hour and grabbed his friend's arm as the other rose to leave. "Hey, Enma one of those days?" Enma nodded and Tsuna continued "you know what you need to do?"

The Simon looked at him and lashed out "what?" it was like a whip against Tsuna's skin until he saw the regret that instantly crossed the others face.

"do your homework and eat early and sleep. In the morning things won't be as bad…in fact why don't you and I go to my house and do the homework together?" Enma pulled out his phone and texted the others and the two went to see a certain home tutor about English.

The two were subject to a pre-test by the demonic little baby and to their surprise the both made 100s… or so Reborn let them think. His real plan was infinitely more devious. He gave them "juice" as a reward. Soon the two were entirely smashed and speaking in perfect English as if they were natives. Reborn called the celebration over and two inebriated boys went to drop Enma off.

After dropping the boy off Tsuna staggered more or less in the direction of his house until he saw a familiar shadow peel away from the darkness. He chased after it until he caught his quarry. "gocsha!" he wrapped his arms around it.

Hibari blushed. She was caught by her drunken boyfriend spying on him. Soon the two were in the Committee room. Hibari was on the couch with Tsuna pumping away. She was lost in heaven. He was…well, not so much. After all the alcohol he was stuck. After hours he started to sober a little and finally came. Kyoya kissed the exhausted boss and whispered in his ear "Don't ever leave me alone that long again or I'll bite you to death…" he nodded and fell asleep holding the violent women in his arms. He didn't see her gentle smile as she curled into his arms.

The week after that particular rendezvous Tsuna announced he and Enma were going to Italy for a week to conduct the official alliance ceremony between the Simon and Vongola. The family was heartbroken at the thought of being separated from their dear boss. The next day the two bosses set out for Italy on the Vongola private jet. The luxurious interior was built for comfort. They sat in two recliners across from each other. Enma was asking advice about relationships due to an odd set of circumstances with a certain ice queen. "…so your saying you pretty much got molested into everything?"

Tsuna rubbed the back of his neck and nodded. Reborn sat on the Tsuna's shoulder and took in everything with a smirk. As Enma wandered off to the toilet Reborn hissed into Tsuna's ear "as an ally you should help him…" and Tsuna picked up the hitman's smile and called Kyoya.

She answered with her usual greeting "Herbivore…make this quick I'm in the middle of biting some assholes to death"

He chuckled "Love you too" he could feel her blush over the phone "I need you to do something for me"

A tonfa fell and some poor sucker groaned as the hardened metal broke some bone. Tsuna sympathized, Kyoya was into a little S&M play and, for her, tonfa use in bed was spelled O-R-G-A-S-M. "If it has to do with the others…" she growled in warning

"No, no I need you to talk to Adelheid, see how she feels about Enma"

She hissed then sighed "You owe me…" they said goodbye (okay, he said goodbye she growled and hung up). Both tutor and student smirked as their target walked in.

The business in Italy was grim and long. Every decision and agreement was worse than pulling teeth. Everybody fought everybody just because they could. The fourth day was the worst. By far. One particular boss that was a giant pain in the ass was griping about his wife never let him fool around with other women. Tsuna, having not seen Kyoya in a week, was irked. This man had the gall to bitch about his wife, whom he had brought along. Tsuna audibly growled and the room fell silent. When the sweet innocent guy growled shit was about to go down.

"don't say another word. Kyoya is thousands of miles away and I haven't seen her in seven days. You think you have a problem? Do you even realize who she IS?" the subject of the lecture looked annoyed until Iemitsu hit play on his phone. It was a video of Hibari biting a guy to death. The man paled and winced before looking at Tsuna. The Vongola's saccharine sweet smile would give the man nightmares.

Tsuna sat back smiled again at the man who shuddered. What type of man could keep that hellion under control?

After the meeting was over Tsuna looked over to his father who grinned and pulled the two boys over. "let's go home" Tsuna was at the airport faster than the car.

As the plane climbed to an altitude of several thousand feet Tsuna looked around at those who were with him on the plane. Iemitsu and Enma were deep in a discussion about which bosses would be trouble and who would be alright for the young Simon to meet. As the two continued to talk Tsuna snuck away and called Kyoya. As he hung up an odd expression came over his face. There was only so much a meddler could do.

A week had passed since he had gotten back and Tsuna was on his first official date…since everyone knew. As the two passed a certain café Tsuna recognized two figures sitting at a table chatting. As he said his greeting the two looked up.

Bianchi blushed "so you caught us on a date…" Tsuna nodded "don't tell anyone…?" her hopeful face made it impossible for him to deny her.

As Kyoya and Tsuna walked out Tsuna tossed a wink over his shoulder and laughed at the blush that ran rampant over the two faces.

As the pair walked by the park Tsuna wondered what would be in his future with his family and this little hellion.