Hey everyone. This is my first, in a long time, M-rated one-shot. Please note that I haven't written something like this in a long time. And while I'm writing this, it's completely embarrassing. I feel like I corrupted Tsuna. Wah! Reborn is going to kill me if he finds out! I can't believe I wrote this sort of stuff when I was younger… I do not own KHR. Not meant for young readers. You have been warned.

Hands-On Lesson

LoveOneself

Throughout his life, Tsuna never felt this much embarrassment in his entire life. He wished he could come to his senses and hide under a rock in a faraway place. If only that was an option. First is because his ten year later self is not going to allow such a thing. Second would be because he was drugged by an aphrodisiacs pill his older self gave to him. Apparently, he said that it was a candy. Unfortunately, that was a lie. Now, he's sitting on his older self's lap with his hands tied behind his back naked. That's the start of the embarrassing part. Second would be that his older self is thrusting his erection inside him. But that's not what made Tsuna feel embarrass that he wanted to hide forever. The main reason is because Yamamoto is sitting in front of them, watching.

"Do you like the fan service Yamamoto?" Older Tsuna asked.

Yamamoto didn't say anything. Not that any words could form that is. Even if it did, the words wouldn't come out right and become mutterings. Older Tsuna smirked as he lightly bit Tsuna on his ear. Tsuna, holding back as much as he could, moaned in response. He didn't know what to do or say anymore. His mind was getting blurry to the point that he couldn't think. Then again, he was drugged. And he can bet that his older self was enjoying every minute of this. The older brunet leaned back slightly and spread the younger brunet's legs apart wider than necessary. That left him exposed to his Rain guardian who is still watching them, dumbstruck. Words became lustful moans as he tried to speak. Apparently, talking failed miserably.

The reason of how this came about was all the Ten Year Bazooka's fault. He really needs to hide that thing from the Lightning guardian. Apparently, the Bazooka was being abused by Lambo from his random choice of playing. That was when it started to malfunction. And instead of transporting Tsuna to the future when it landed on him, his future self showed up right next to him. Lambo ran out of the room to avoid getting into any more trouble. Adult Tsuna was questioning where he was and how at the sudden change of surroundings. When younger Tsuna explained to him where and how, the older male thought he could have a little fun. That was when he gave the younger male the 'candy'. And Yamamoto was here the entire time it all happened. And this is how they ended up like this.

"I never thought I was so sensitive when I was younger."

"Sto-ah! This… This is… Ah!" Tsuna moaned.

"Do you really want me to? But I thought you like doing this while Yamamoto watches."

"That's n-not the case."

"How cute… Do you know you get tighter whenever I mention Yamamoto's name?" Older Tsuna whispered.

Tsuna gulped at the comment. This is embarrassing. This is really embarrassing. He couldn't handle it anymore. How could a study session with Yamamoto turn to a sex performance? Luckily, Reborn and Gokudera isn't in Japan to see any of this. Tsuna release a sharp gasp as he felt the older brunet suck on his delicate neck harshly. After this, he could guess that it'll bruise up soon. His large hands wander on Tsuna's chest, increasing the pleasurable feeling. It didn't stop there. No. Adult Tsuna wanted to be a bit daring for a moment and finish it in one shot. He thrust faster and harder into the once virgin hole. Tsuna continued moaning louder and louder with every hit.

"Yes, that's it. Moan louder for Yamamoto. Show him your erotic side." He whispered seductively.

"Yamamoto… Yamamoto…" Tsuna called out silently.

The response made the older male satisfied. Tsuna felt his sanity slip as his vision became blurry from lust. On the side, Yamamoto's blush took control of his face. Not to his cheeks or ears but the entire face was brightly lid with red. Never in his life did he have thought about seeing this. Sure, he saw some girls in magazines. But those girls didn't expose anything important when his baseball teammates were showing them. But this is what others would call first class seats. And the Rain guardian is uncertain whether he should be happy to watch it or get worried and stop it. However, a certain something between his legs already knew what it wanted.

Tsuna clawed harshly onto the ropes. He couldn't handle it anymore. He was seeing stars and flashes as the thrusting increased. Older Tsuna was enjoying himself as he stroked Tsuna's leaking erect. The moans that were weakly held back escaped the younger brunet's lips. With every thrust, he became louder and shameless. He was getting close. The older male knew it. The movement of his hands and hips became rough. Yamamoto gulped at the sight before him. In one final thrust, Tsuna didn't hold anything back. His toes curled and back arched. His body shook as he felt something fill him up inside. The brunet himself wasn't looking any better. On his chest was his own semen running downward to his stomach. Adult Tsuna removed his younger self and gently placed him on the bed. He sat on the floor after.

"That was fun… I wonder if he can last another round." Adult Tsuna whispered.

"I don't think he will last for another one. And the effect of the pill should wear off." Yamamoto answered.

"Oh…? Is that so? Ne, did you like the show Yamamoto? I noticed how you looked at my younger self."

"W-What are you talking about? I didn't…!"

Adult Tsuna merely chuckled at the poor attempt. His brown eyes trailed to his younger self then to Yamamoto. He smiled as an idea came along. There were a few things about the pill that he gave to younger Tsuna. Like other pills, it did have a time limit of how long it will last. The upside is that it didn't reach it yet. If the once innocent brunet wakes up, he'll just feel the same sensation like before till he is able to release it once more. Yamamoto and Tsuna's eyes locked for a minute. His idea swirled around in his head. It was becoming more appealing and desiring as it was thoroughly thought out. Yamamoto didn't feel comfortable. No one would if they were in his place. And the fact that adult Tsuna was staring at him made it worse.

"Hey Yamamoto… Have you ever wanted me?"

"What are you saying? I never once thought of that before!"

"Oh please! I've seen how you looked at me. Even your body can't deny it. I bet you wanted to be the one pleasuring my younger self."

"That's… I… Tsuna doesn't see me like that. I'm only his friend in his eyes. And that's what I'll be."

Playing the suffering hero, are we? Adult Tsuna could have figured. If it wasn't for him being here, the future would have ended differently for the two. His younger self, if he recalls, developed feelings for the Rain guardian five years from now. Alas, they were unable to be together. Being a famous Mafia boss is hard work and time consuming. Being a guardian is no different. This was probably destiny's way to say 'Sorry for screwing with you. Here's your reward.' It's a pitiful sight to see someone being friend-zoned for so long. Then again, he was chasing girls when he was younger. The thought of dating someone of the same gender never came into mind. Yamamoto ran his hand through his spiky black hair.

"I really liked Tsuna for a long time. Since we first met… But after this, I doubt he would look at me again."

"Don't jump to conclusions so early. How about we play 'cause and effect'? Interested?"

Adult Tsuna could notice the hesitation. Yamamoto nodded his head in agreement. The older brunet smiled slyly. How long has it been since he had so much fun? He couldn't remember. The only thing that was considered fun was doing paperwork all day than going to meeting with old people. He explained what he had in mind. He began with the pill's time limits. Apparently, it's still in effect. All they need to do was wake the sleeping boy up. Yamamoto expressed his concern but didn't voice it. Tsuna continued on. After the younger male wakes up, the Rain guardian takes his chance to claim his younger self as his. Not only will it help Tsuna calm down, but allow the baseball lover to confess his love. If he is willing, that is. And the two of them getting together is very likely.

"What do you say? It's like hitting two birds with one stone."

"I… I don't know. This might not end well."

"Trust me. I'll even teach you how to pleasure me."

Yamamoto nodded slowly. Adult Tsuna smiled at how well his plan is coming along. The next step was to wake up the sleeping brunet. Older Tsuna sat on the bed and gently shook the younger brunet. He softly whispered his name in his ear. Before they knew it, Tsuna woke up slowly. He sat up on the bed tiredly, rubbing one of his eyes. Yamamoto was feeling nervous. He had never done something like this before. He knew that he had to one day when he had a lover in the future. However, that didn't go as plan. Adult Tsuna was using his charms to seduce younger Tsuna again. It didn't take long before Tsuna was in the mood for another round. The older brunet pressed one finger on the other's lips. He gestured the Rain guardian to step closer.

When Yamamoto was in Tsuna's sight, he licked his lips playfully. The baseball idol knew what was going through his dear friend's head. He didn't know if he should be excited or nervous about it. Should this be considered taking advantage of someone? Adult Tsuna doesn't think so. The mess from Tsuna's recent activity was cleaned up. The younger brunet moved closer as he smiled seductively. Yamamoto gulped. It was too late to turn back now… The Rain guardian sat at the edge of the bed, in front of Tsuna. He could see brown eyes filled with lust and desire. It was something that he didn't expect from his close friend. Should he even think they're friends anymore after this? No one will know.

"Hey Tsuna… Yamamoto must be feeling lonely. Maybe you can entertain him." Older Tsuna said, smiling slyly.

It took just that for Tsuna to let loose again. The brunet held Yamamoto's cheeks in his hands and kissed him. In a way, it was both their first kiss. During their early performance, kissing wasn't involved at the slightest. Adult Tsuna smiled at how deep the kiss was. Yamamoto felt like he was getting sucked into it, wanting more. Both tongues swirled around against one another for dominance. Eventually, Yamamoto came out as the winner. Tsuna would occasionally moan as Yamamoto deepens the kiss. And from that, he was enjoying it very much and wanted more. Tsuna took this chance to lead Yamamoto further in on the bed. Following the brunet, the kiss didn't end at the slightest. Adult Tsuna stood up and sat on the desk near the bed, watching.

"Yamamoto, make sure you make him aroused. Make him want more of you." Older Tsuna informed.

And that's what Yamamoto is going to do. He pulled away from the kiss and stared at Tsuna. The brunet was taking deep breaths from the lack of oxygen in his lungs. While Tsuna was distracted, Yamamoto focused on going further south of his partner's body. The feeling of his lips on the brunet's soft skin made him excited. He is really doing this. He's really making love to Tsuna, his longtime crush. The kiss began with the neck and down to the chest. Yamamoto licked one of Tsuna's nipples while his hand fumbles with the other. The brunet gasped harshly. Older Tsuna was right. Younger Tsuna is sensitive. Yamamoto did this for a while, giving equal attention. He resumed going further down.

"Yamamoto… Yamamoto…" Tsuna whispered.

Excitement and nervousness overwhelmed Yamamoto. The fact that Tsuna was calling his name made it clear that it was not a dream. He trailed down from the stomach to the legs. He wanted to tempt the brunet a bit with what he saw earlier. He began to kiss it lightly. After that, it came much rougher. Yamamoto sucked on the soft skin, leaving a noticeable love mark. That'll remind Tsuna of what they were doing later. The brunet watched, ready to burst from wanting more of Yamamoto. His hands clenched around his blushing cheeks. Every spot that the Rain guardian touched burned. His body was becoming warmer every second.

"P-Please… Please take me…" Tsuna begged.

Older Tsuna smirked at Yamamoto's accomplishment of arousing his younger self. It was a sight to see. Who would have thought an inexperience Yamamoto would be a natural at this? He sure didn't. The Rain guardian stared at the whimpering brunet before giving in to his begging. His heart was beating so hard that he could almost hear it. He slowly spread Tsuna's legs apart, giving himself a perfect view of the twitching erection. He could visibly see clear liquid dripping out at the tip. Yamamoto licked his lips before doing the same to the brunet. Mixture of a moan and a gasp escaped Tsuna's lips as he felt Yamamoto's tongue connecting with his twitching cock.

"Ya-Yamamoto! A-Ah!" Tsuna moaned.

"You're doing a great job Yamamoto. Now, just have him 'release' first so he can relax better."

Yamamoto just kept going, keeping what adult Tsuna said in mind. He needs to get Tsuna to relax. So, he continued on licking, sucking, and gently nibbling it. The sounds of the brunet moaning were music to his ears. When the brunet was doing it with his older self, he didn't sound so… lewd like this. He could have guessed that Tsuna let himself go this time. The young brunet's breathing became faster as his Rain guardian continued on what he was doing. He couldn't help but to moan out again as his body was getting hotter. Some sense in him said it was the pill that was causing him to behave that way. And other half said that he should screw logic and let him have fun with Yamamoto.

"Y-Yamamoto, I'm…! I'm a-about to–!"

It was already too late. The pent up feeling that was forming in his stomach and lower half was gone. However, the warmth was still there. Tsuna's half lidded brown eyes tiredly wandered to his partner in front of him. He could see Yamamoto sitting up with the back of his hand near the corner of his lips. He swallowed his semen. Tsuna slowly sat up and settled his hands on both Yamamoto's shoulders. He closed his eyes as he leaned in, licking the remains on the other side of the Rain guardian's lips. He quickly pulled away and opens his eyes, blushing at his action. Yamamoto soon found himself doing the same thing. His heartbeats became rapid at the thought of how seductive Tsuna was being. If this was actually a dream, he wished it would never end.

"Now, that you completed that, we can move on. Next step is to prepare him." Adult Tsuna informed.

"How do I do that?" Yamamoto asked.

"Leave that to him."

Yamamoto's attention on the older brunet trailed back to the brunet in front of him. Tsuna took one of his hands and drew it near his lips. His tongue carefully moving around his three fingers, making sure it was extra wet. Yamamoto watched, dumbstruck. The sight he never thought he would see is in front of him. He mentally screamed in joy. And the chance of fainting on the spot was high. However, he held it in and used his willpower. There is no way he is going to miss this for anything. Tsuna pulled away when he knew it was wet enough. He crawled away on his hands and knees on the bed. After that, he turned his head back to look at Yamamoto. He spread one of his bottom cheeks, indicating he wanted Yamamoto to take him. His blush didn't fade from his cheeks.

'Dear Baseball God… Please have mercy on me…' Yamamoto thought.

Older Tsuna was practically smirking at the sight. He could imagine how Reborn would love to get his hands on this for blackmail. Alas for him, that's not going to happen. The older brunet licked his lips with content at his younger self's performance. He only had one go and already he knew what he was doing. And the same goes to his Rain guardian. Yamamoto drew himself closer to the younger brunet. He's really doing this. He is really doing this. He positioned himself better before doing anything. He firmly held Tsuna's hips. Yamamoto gulped. It was just moments away from him making love to his crush, becoming one with Tsuna. Tsuna began to whimper.

"Yamamoto… I want you inside of me. Make me yours…" Tsuna whispered.

Most of Yamamoto's common sense and sanity cracked at that point. He wanted to just shove himself inside the small body and rampage in it. However, he held himself back. He didn't want to hurt Tsuna in any way. He held his twitching erection and pressed it against Tsuna's entrance. The brunet mewed at the action. It took a while to get himself fully inside from the slow pace. However, it was worth it when Tsuna didn't experience any pain. The feeling of his cock being inside Tsuna's tight little hole made the Rain guardian gasp sharply. Tsuna clung to the bed sheets as he stuffed his face halfway on his pillow. He could feel something inside him, twitching. The size was a bit difficult to adjust at first since it was a bit bigger. But now he's okay with it.

"I-It's okay to move now…" Tsuna said.

"Okay… I'll start slow." Yamamoto answered.

The thrusting began as how Yamamoto said it to be. The slow pace was for the brunet to adjust a bit more. Tsuna would even make small moaning noises as he thrust inside. Yet, the calm Rain guardian found it much difficult to hold back. Every movement, every thrust, Tsuna would tighten himself around him and untighten. It was pleasurable yet torturous. It was if Tsuna was teasing him. Yamamoto smiled slyly. Pulling out, he slammed back in with much force. A loud moan escaped Tsuna's mouth. His back arched and toes curled at the sudden sensation going through his body. It was the same feeling his older self gave to him. But this one was much stronger.

"Ya-Yamamoto, more…! I want more…" Tsuna said.

"Don't worry Tsuna… I have much more to give."

The pace became much faster and hard as minutes went by. Yamamoto was holding onto Tsuna's hips to steady him. The sound of skin smacking into each other echoed in the room mixed with Tsuna's moans and Yamamoto's groans. Tsuna was practically seeing stars whenever Yamamoto went deeper inside of him. The Rain guardian's cock would hit that spot in him that sent nothing but blissful pleasure throughout his body. It was more than enough to drive him on edge. One of his hands released the bed sheets and wandered to Yamamoto's leg, using it as a gesture to make his partner go faster and harder. And Yamamoto did. There was no holding back from him.

"Ya-Yamamoto! Ah! I… I–"

Tsuna's words faded away when his sanity slipped away. His grip on Yamamoto's leg loosens as he drew it back to the bed, clenching on the sheets. The words didn't make it to his partner's ears. The brunet wasn't the only one feeling pleasure. The Rain guardian kept a steady pace, pleasing the both of them. Even if it's just Tsuna's back that he's looking at, he knew Tsuna was enjoying it like he is. He leaned further in, resting his stomach on Tsuna's back, and laced his fingers with the brunet's. It felt as if they were the perfect match. Even though it feels special now to him, it'll be meaningless once it's over. Yamamoto bit his lips when he felt a sensation stirring in his stomach.

"Y-Yamamoto… I… Ah! I– I can't hold back anymore!"

"Me too Tsuna… Together… Let's do it together."

Saliva trailed down from Tsuna's open mouth. He could feel the same pent up sensation stirring inside of him. His grip on the bed sheets tightened, making his nails form red crescents on his palms. One final thrust was all it took for Tsuna's bed to be covered with his white semen. His legs shook weakly from the ejaculation and with the feeling of being filled up again. Yamamoto was even losing his steady as he tried to hold himself up. Tsuna could feel liquid dripping down his thighs. The Rain guardian slowly pulled himself out and rest next to the brunet. He breathed heavily. That took a bit of energy out of him. Slumber overcame Yamamoto as he slowly closed his eyes. Before he could, he whispered a gentle 'I love you Tsuna'. Tsuna smiled at his partner before turning to his future self.

"So…? How was it? Was it better than what you expected?" Adult Tsuna asked.

"Yeah… Yamamoto was perfect. Thank you for helping us." Tsuna replied.

"How long did you know that the time limit was over?"

"For a while… The Vongola Hyper Intuition shouldn't be taken lightly."

Older Tsuna smiled and said that it was about time for him to leave. He stood up from the desk and walked over to his younger self. Patting younger Tsuna's head, he asked for one last favor before he goes. The brunet agreed to it as if he already knew it. The request was simple. The relationship of his younger self and Yamamoto was up to them to decide. But he would like to know what they are in the future or how it all ended. Unrequited love is quite painful if he thought about it. So, he requested for a ring. A single ring, whether it may be simple or fancy, will indicate if the two of them are together as lovers. If he doesn't find one in the future, then he'll know that they have remained as friends. Adult Tsuna smiled tenderly.

"So, can you do that for me?" He asked.

"Of course…"

With that, the older male left with a pink poof.

Tsuna found himself in his bedroom when he returned to the future. His hand ran through his messy brown hair. He was on his bed with his silky pajamas on. He sighed as he looked around. It was only him in here as far as he could see. Tsuna closed his eyes tiredly and turned to his side on the bed. Maybe it was all a dream. If it was, that was one vivid dream he had indeed. The sound of light snoring made the brunet reopen his eyes. In front of him was a sleeping Yamamoto. He screamed inside from the sudden shock. After some given time, he settled down his nerves and observed his Rain guardian. His confusion turned to happiness after one single sight. On Yamamoto's left hand was a simple orange ring. He soon noticed one on him. He removed it to examine it. On the inside of it, it said 'Rain + Sky = Forever'. He smiled.

'We're finally together Yamamoto…' He thought happily.

He leans closer to the Rain guardian, kissing him on the cheek. Tsuna snuggled next to his lover, allowing sleep to take over.

I am now going to go to a wall and bang my head on it. This! This! I'm sorry Tsuna! I corrupted you! I can never see Tsuna the same ever again… I'm really scared of what you guys will say about this story. It was planned out before but I had no intentions of finishing it. My motto for writing is "Always finish what you started. No exceptions!" So, I finished this. This is for one of our dear writer here. But I'm not sure if he's still interested in reading this… I'm going to continue writing T-rated stories till this fades out of my head. Anyways, goodbye and please review… Though I'm still scared of what you guys will say…