"That's all for today's class. Any questions?"

"Yes! I have a very serious question to ask!!"

Jongwoon pretended that he didn't see the good-looking young man who raised his hand with a huge grin on his face.

"No? Then you all are dismi—"

"Professor Kim," another young man who sat beside that kid called him while chuckling, "Kyuhyun seems like he wants to ask you something."

Jongwoon almost failed to suppress his groan. Now that another student had pointed out, he couldn't pretend that he didn't see that kid anymore.

"Sigh, fine, Kyuhyun, what do you want to ask?"

The handsome young man, Kyuhyun, straightened himself up and smiled at him.

"We learned about basic solutions used in manufacturing industries today, right? Jongwoon hyung—"

"Please call me professor Kim."

"—Professor Jongwoon hyung, so, I was wondering, is there any solution that I can use to melt the wall around your heart?"

Here it is.

Jongwoon sighed while his students were giggling and cheering loudly. Everyone had a teasing smile on their faces but the person with the brightest smile was no doubt Kyuhyun. Pinching the bridge of his nose, Jongwoon ignored his crazy heartbeat and kept a straight face while retorting back.

"Such a thing probably doesn't exist so you'd better stop looking for it."

"I beg to differ, hyung, before Alexander Fleming invented Penicillin, no one would have thought that there could be broadly effective antibiotics like that."

Kyuhyun winked at the older man.

"That means there must be a way to get past your iron wall. I just have to keep trying until I found it and made you mine!"

This time, Jongwoon completely failed to stop the blush from creeping up on his cheeks.

"C-Class! Dismiss!!"

Ignoring the loud cooing from women and whistling from men, Jongwoon snatched his bag from the table and stomped out of the lecture hall. He also pretended that he didn't hear Kyuhyun shouting "you're too cute for my heart!" as he slammed the door shut behind him.

****************************************

Throwing his bag on the desk, Jongwoon groaned while slumping down on the swivel chair. Leaning back into the leather chair, he closed his eyes and massaged his temples with a deep frown.

"That kid is at it again?"

Peeking one eye open, Jongwoon merely gave a curt nod and quietly hummed to his friend. Kim Heechul, the Physics professor, snorted while leaning on the Chemistry professor's desk.

"You'd have just gone on a date with him already. It's not like you didn't like him or what."

"W-What are you talking about Heenim!!? Of course, I only think of Kyuhyun as a student!"

"You said that even though your cheeks are redder than a red marker? Pfft, Jongwoon, even the brat who cheated during my exam and got caught still lied better than you. Admit it, you like that kid and actually enjoy his flirting."

"No! Heenim, you got it all wrong… like… we're a professor and student and I'm older than him so that's inappropriate."

The Physics professor rolled his eyes hard at his friend's answer.

"Jongwoon, you're only twenty-seven and that kid is already in his second year. Both of you are an adult now so who cares if you date or your student."

"Heenim!!"

"I care about you, dude, else I wouldn't bother to bring it up. I'm being serious here, Jongwoon. Life is too short to play hard to get, so you'd better listen to your heart."

With that said, Heechul ruffled the younger professor's soft hair and left him to his own thoughts.

**************************************

"Life is too short to play hard to get, so you'd better listen to your heart."

"Argh! I can't focus on my report at all!"

Jongwoon complained to himself while pulling his hair in frustration. Right now, he was alone in the science department office, trying to get his report done but to no avail. He just couldn't get what his best friend said out of his head.

"Jongwoon hyung! I'm here for the daily courting!"

"Great. Just what I want now, more distraction."

Jongwoon murmured under his breath but made no move chasing his student out. Kyuhyun sat down opposite his professor wearing a huge smile on his face. Propping his chin in his palm, the younger man openly stared at the older man with a loving gaze. Obviously, Jongwoon noticed it and was greatly bothered by it.

"Why are you even here?"

"Because you're the other hydrogen to my hydrogen oxide that will give me life."

"That's a really lame pick up line, Kyuhyun."

"But it made you smile, right?"

The dashing student said while staring at his professor, his gaze soft and gentle. Jongwoon tried really hard not to admit it but he couldn't stop the corner of his lips from rising. Eventually, a light giggle escaped from his full lips.

"Fine, you win, but that can't be your only reason coming here, right?"

"You know me too well, hyung. Actually, I want you to help with my homework."

"Alright, what is it?"

"It's a simple physics problem, you know, finding the distance between point a and point b and how much time it takes to reach it. Problem is, the question didn't provide any information about point b so I don't know where to start."

"Hmm, that's a rather tricky question, for sure, but you should ask professor Heechul than me."

Kyuhyun leaned in, "no, hyung, you're the only one who knows the answer."

"What? Is it a problem that I've seen before? What is it then?"

Kyuhyun winked, "what is the distance between my heart and your heart, and how long does it take to win yours?"

Jongwoon literally rolled his eyes and snorted, though the heat also started to paint his cheeks bright red.

"Kyuhyun, really?"

"Do I really love you? Yes, I do. Also, you gotta at least admit that my pick up line is creative."

The professor shook his head but his dark eyes and pale red lips were smiling.

"Creative, maybe, cringe and lame? Totally."

"Ouch, but, hyung, you're gonna love this one!"

Jongwoon raised his brow, "there's more?"

Kyuhyun smiled smugly and took out a folded paper from the jeans pocket.

"Remember what I asked you this morning? About the solution to melt the wall around your heart? Actually, I finally found it!"

Frowning curiously, Jongwoon took the paper and unfolded it. Written neatly on the white paper was a strange chemical formula that he had never seen before.

"What is this weird formula? Kyuhyun? Iodine, lutetium, vanadium, uranium, di manganese oxide, nitrogen—"

Jongwoon stopped and took another look at the paper. After a short while, the Chemistry professor started to blush madly.

I + Lu + V + U + 2MnO2 + N+ Ba + C + K

"So? That's a perfect formula, right?"

Kyuhyun asked with a smug smile. It took Jongwoon who was blushing redder than the sun almost four minutes to find his voice again, his best friend's words still ringing in his ears.

"Actually, no, this formula is incomplete so it's not perfect yet."

"What? How can that be?"

Ignoring his student who looked genuinely confused, Jongwoon took his pencil and added something to the formula, before handing the paper back to the younger man. Kyuhyun only had to briefly glance at it to break out into the brightest smile.

(I + Lu + V + U + 2MnO2 + N+ Ba + C + K)2

"N-Now that's a complete and perfect formu—"

Chu!

Jongwoon's eyes almost popped out when Kyuhyun suddenly closed the gap between their faces and kissed him. Although it was only an innocent butterfly kiss, the gentle touch already set his whole body on fire. The older man could only sit there dumbfounded when his student stole another quick peck.

"As expected of Jongwoon hyung," Kyuhyun said with a happy smile after pulling away, "I still have many things to learn from you. That's why,"

Kyuhyun reached out to take his professor's small hand in his.

"Please let me be by your side and observe you forever, Jongwoon hyung."

Jongwoon huffed in annoyance but quietly tightened their holding hands.

"Hm! It's not like I like you or what, but, since I won't be able to shake you off anyway, might as well deal with you as quickly as possible!"

"If saying that will save your pride, hyung."

Kyuhyun chuckled and leaned in for another kiss, but prolonging it this time.

And Jongwoon made no move to stop the younger man.