A/N: hi so this is my first time attempting to write smut, it won't be good but I tried. thank you.
"Hello Class, today we're going to be talking about semen," Changbin said, walking in front of his classroom, pacing before his desk. He didn't look uncomfortable one bit which worried Jisung only slightly.
"The glucose content of normal human semen amounts to 0.41 +/- 0.09 mmol/l. As there is a negative correlation between this sugar and sperm motility, it must have an important role in the metabolism of these cells,"
"Cervical mucus is very rich in glucose and does not contain fructose," Changbin said, taking off his glasses and rubbing his eyes and cleaning his glasses, pushing his hair back and fixing his shirt.
"The rest of what a man ejaculates in his ejaculate, which is about a teaspoonful (5 ml), is made up of water, sugar, protein, vitamin C, zinc, and prostaglandins. Semen or seminal fluid is the mixture of sperm and the secretions of the seminal vesicles, prostate gland, and the bulbourethral glands."
Changbin looked around at the confused faces in the class, his words clearly going in one ear and out the other. He sighed aggressively before repeating in smaller words for his 'dumb' class,
"Sperm is made of glucose; does anybody have any questions?"
He looked around, no one dared to stick the hand up.
The bell rang just in time and everyone scrambled, packing up their belongings and getting out of the class as fast as they could.
All except one student.
"Yes, Jisung?" Changbin raised his eyebrow at the boy.
"So you're so saying that sperm has sugar in it?" Jisung asked in a quiet voice.
"Yes, that's what the whole lesson was about. Did you not listen?" Changbin responded, getting a bit irritated.
"That's weird, so why doesn't it taste-" Jisung started before cutting himself off.
"Excuse me?" Changbin moved closer to Jisung, watching the latter step back in fear.
"N-Nothing, Sir-" Jisung rushed over to his desk, picking up his things.
Changbin walked up behind his student and pressed his now prominent bulge up against the latter's ass, grinding against him ever so slowly. He felt Jisung tense up, grabbing onto his waist and massaging it to calm him.
Jisung, feeling the pleasure, tilted his head back and whining, grinding back against Changbin. This only made Changbin grip onto his waist tight enough to leave marks.
"Want to finish your sentence from before off for me?" Changbin growled lowly into Jisung's ear, gently biting the latter earlobe until he heard soft mewls coming from the boy.
"I-I was saying... i-if s-sperm has sugar in it, why doesn't it taste s-sweet? W-Why is it b-bitter?" Jisung cried out, not wanting to embarrass himself like that in front of a teacher. Changbin only sniggered, trying to hold back a fit of laughter.
"And how would you know it's not sweet?" He asked genuinely, he knows that it's what they're going over in tomorrow's lesson but this was only because he wanted to embarrass his student further. Jisung only shook his head, pursing his lips shut.
"Ah, ah, ah. When you're asked a question, it's respectful to answer." Changbin snarled. Jisung let out a shaky sigh.
"A-All the sperm I've t-tasted was bitter, salty and smelt like chlorine,"
