It started with a dumb, childish fight when they were six years old.

"Dolphins are mammals, Dean."

"They live in the water, Cas. They are fish. Don't be stupid"

Dean and Cas had met a few months earlier on the first day of kindergarten and they had been friends ever since. But in that moment, Cas wanted nothing more than hit Dean.

"I'm not stupid," he huffed and crossed his arms. "You're stupid."

Dean squinted at him and crossed his own arms. "Whatever. I don't want to talk to you ever again."

"Fine."

So the boys went their own ways and didn't talk nor look at each other the whole day. Cas didn't even think about Dean. He could have fun on his own, he didn't need Dean. When it was time to go to bed, though, Cas started to have regrets about their fight. Dean was his best friend, after all. He decided to apologize tomorrow, even though he was right.

In the morning, when he entered the kindergarten classroom, his eyes searched for Dean. He hoped his best friend wouldn't refuse to talk to him.

Having found him, he ran to Dean's side and made sure to have Dean's attention.

"I'm sorry," Cas said and was surprised to hear Dean say the same words at the same time.

"Why are you sorry, Cas?" Dean asked and rubbed the back of his neck. "You were right. I asked my mom and she said dolphins are mammals. And she knows everything, so it means you were right."

"I'm sorry I told you were stupid."

"Well, I guess I am," Dean said and looked at his shoes.

Cas shook his head. "No, you're not," he said sharply, "I only knew this because my sister told me. She goes to third grade and she knows a lot."

"Oh," Dean said and gripped Cas' hand. "I called you stupid too, I'm sorry."

"It's okay, Dean." Cas started to smile, but at that moment Dean pressed a small kiss on back of Cas' hand and Cas' eyes widened in surprise.

"What was that for?"

"My dad always does that after he and mom had a fight."

Cas felt his cheeks burn and he lowered his gaze. "Thank you, Dean."

After that incident, kiss on the hand became Dean's way of apologizing. Well, while they were kids. Once their puberty hit, the kisses stopped.

Cas stormed into his room and slammed the door behind him. Dean had crossed a line today and Cas didn't know how to calm down. They didn't fight often; Cas could probably count on the fingers of one hand every big argument they had in twelve years of their friendship. For that reason, he was left so rattled.

He didn't understand what Dean's problem with Meg was, but it had to stop. Meg was a classmate of his and he had spent a lot of time with her in a past month, working on a project, and every time Dean had seen them together he would make incredibly rude and mean comments about her.

As he sat on his bed and took a deep breath, someone knocked on his door.

"Go away."

"Cas, please. Let me talk to you. I'm sorry, okay?"

"No, it's not okay."

"Cas," Dean said and opened the door.

"I didn't say you could come in."

"Look, I was a dick, I know, but I apologized to Meg."

"I don't what has gotten into you, but she doesn't deserve that kind of treatment. She's always kind and nice towards me and she's my friend."

Dean looked down at the floor and swallowed hard. He really did seem ashamed of his actions, Cas thought.

"I know, Cas. You have no idea how sorry I am. The words just kept leaving my mouth and I-I…" Dean took a deep breath and sat down next to Cas. "I guess I was jealous."

"Jealous?" Cas cut in, surprised.

"Yeah, you two were spending so much time together lately and-"

"We were working on a project. For school."

"And you were getting along, it looked like you really enjoyed her company, so I…" Dean trailed off.

"Did you really think that she would replace you, that I would forget about you? Dean, you're my best friend. The most important person in my life."

When Dean looked at him with wide eyes, Cas realized the weight of his words and felt his face flush from embarrassment. Fortunately, Dean didn't say anything. Instead, he grabbed Cas' hand and pulled it towards his lips, pressing a gentle kiss and leaving Cas in shock.

"You too, Cas," Dean murmured.

His words pulled Cas out of trance and he tugged his hand out of Dean's. "Don't do that," he said as he got up from his bed, moving as far as he could from Dean.

"What, why?" Dean looked hurt and Cas regretted his harsh tone.

"It makes me uncomfortable."

Cas averted his gaze as his throat tightened. He couldn't stand Dean kissing his hand when his whole being craved for more, for something Dean wouldn't want to give.

Dean let out a dark chuckle. "Why? 'Cause it's gay? Didn't peg you as a homophobe, Cas?"

Dean got up and rushed towards the door, but Cas stood in front of it, blocking the way. When Dean tried to walk past him, he didn't let him, and they ended up standing face-to-face.

"Dean, please. You know I'm not."

"Oh, yeah, so it's just me who disgusts you?"

"For fuck's sake, Dean. You don't disgust me," Cas raised his voice.

"Then why?" Dean yelled in his face.

"Because I'm in love with you and I want it to mean more than it does! Okay?"

A silence stretched between them while they stared at each other, shocked by a sudden confession.

"It does," Dean whispered, so quietly that Cas wouldn't have heard him if he wasn't standing so close to him.

"What?" Cas voice, equally quiet, broke slightly.

"It means everything. Cas, I love you too," Dean's eyes were wide and a small smile formed on his face. "I love you so much. I thought you knew."

"You love me?"

Dean nodded.

"You're in love with me?" Cas asked again, because he couldn't believe he was hearing those words.

With a frantic nod, Dean put his hands on Cas shoulders and spoke, "Yeah, yeah. So fucking in love with you."

The smile on Dean's face has grown in a full blown grin, which Cas couldn't help but mirror. They gazed at each other for a few seconds before they burst into laughter. Cas couldn't remember the time he felt so happy.

Dean pulled him into a hug, which he happily returned.

"I thought you knew," Dean repeated. "I mean, I was so obviously jealous of Meg."

"I didn't realize it was in that way... You said-"

"Cas, you have a bunch of friends. Meg is the only one who flirts with you."

"Oh."

"Yeah, oh," Dean said and pulled away from the hug. "Can I kiss you, Cas?"

"Of course."

Smiling, Dean put his hands on Cas' cheeks and leaned in while Cas wrapped his arms around Dean's waist. A second later, their lips met. Uncertain at first, their movements slowly grew bolder, until Cas ended up pressed against the door. When they finally broke apart, they were having a trouble catching a breath.

"That was good, right?" Dean asked.

"Yes, it was. I think I prefer this kind of kiss as your way of apologizing, actually."

"Oh, yeah? I'll keep that in mind," Dean said and dove into another kiss.