A/N: Because Sebaek is more popular than expected, here's another one! I hope you like that one too! ^_^

Chemistry of our Hearts

Once upon a time, Baekhyun was working at his university's labs. Some of his teachers had taken him as an apprentice because he had the best grades of his cohort. Chemistry was his passion since young. He really liked it and tried to study almost everything related to the subject. The thing was: he wasn't the best when it came to equations and it took him many efforts to get to the results he had right now.

That's probably why when Sehun came, he made a point of honour not to be too soft with him.

The guy was only a first year. The teacher seemed to have discovered in him a young genius and offered him a job Baekhyun had worked his off for 3 years before he could set a feet in the lab. It was probably Jealousy. Yep, it most probably was. Not only was Sehun truly talented, he was also naturally good looking.

Sehun was exactly how you could describe the modern genius: lazy, uninterested, know-it-all.  The idea of having someone evolving in his deserved territory caused an intense turmoil inside Baekhyun. He felt invaded and highly betrayed by the teachers he respected so much.

Sehun was the silent type. He did exactly what Baekhyun asked him to do, not without sometimes rolling his eyes at Baekhyun's unfriendliness. He could understand why Baekhyun was upset, so he tried to keep a low profile.

Baekhyun's last results of exams were disastrous. Well, as much as you can call an 82% disastrous. Baekhyun knew it was because he paid too much attention to the new lab recruit. He decided that he would take a hold of himself before he fails his year. He did the first thing that came to his head when the idea of 'taking care of himself' bloomed in his head: he got an haircut.

They were working in silence on Wednesday evening. Out of the blue, which was a little unusual, Sehun spoke.

"I like your haircut. It suits you."

The works made the effect of an electric shock in Baekhyun's body. He wouldn't admit he blushed. (He did.) He changed the subject to hide his embarrassment, which Sehun understood and smiled at.

The next week, Baekhyun bought new shoes. His old Converse were as full of holes as block of Swiss cheese. He chose exactly the same model, except that time they were styled with the logos of his favourite Japanese rock band.

"I like your shoes, are they a special edition?" Sehun broke the silence again because seriously that silent treatment was starting to be ridiculous.

"Yeah, they're sold out everywhere. Took me days to find 'em." Baekhyun mumbled, focus on his experiment.

"You're so lucky! I wish I could have some too. I love that band!" Sehun tried to sound friendly, but not too friendly because he had that 'cold' personality to keep up.

"Yeah, they're great. Now, focus please." Obviously, Baekhyun wasn't ready to be on friendly basis.

The next week, Baekhyun changed nothing. His grades were back to normal and that was all that mattered. Though he was still a little bossy, even if he was slowly getting used to Sehun's presence. He announced their work for the evening a little harsher than he intended. Sehun didn't miss the opportunity.

"I like when you're being harsh on me. I bet you're a dominant in bed." Sehun waved his eyebrows.

It was so unexpected. Baekhyun couldn't stop the heath to spread on his face. What else could he do?! He turned around and reached his workplace.

"Shut up and start working. Those stats won't be compiled by themselves and I plan to leave before tomorrow."

Sehun laughed. He laughed a bright and nasal laugh that startled Baekhyun. It was coming from right beside him. When did Sehun walked so close. He couldn't tell. Sehun trapped the shorter's shoulders with his arm, shaking him a little.

"Come on, Baekhyun. You're so easy to tease. Don't be mad, it was a joke, man!"

"A joke my ."

"It was, I swear! Or maybe I guessed right and you truly are a wild beast!"

Baekhyun threw his elbow in Sehun's ribs, making him take one or two steps back.

"Hmm, Feisty."

Baekhyun had a half side-smile. "Shut up."

End