TITLE: Kinds of Forces

SUMMARY: Tezuka talks about contact forces in physics, and Fuji gives him a demonstration.

PAIR: Perfect. TeFu. FujiTezu. TezuFuji. KuniSuke.

DISCLAIMER: Oh, no…PoT isn't mine. But I'm going to steal Fuji someday…XD

It was a total mistake to yield to Fuji's request to study together. Or to any of Fuji's requests, for that matter. Fuji always had something nasty up his sleeve.

Yet, Fuji had pleaded and wheedled and wouldn't give Tezuka any peace. So Tezuka had no choice but to agree, knowing that he could have been signing his death contract, or whatever.

So on that Saturday afternoon, he found Fuji waiting on the front step. Fuji was lucky that Tezuka was home alone. And Tezuka was the one unlucky, primarily because the tensai was there—and he always spelled trouble.

"Ne, Tezuka," Fuji said as he sat himself on the sofa, "what should we study about?"

"Kinds of forces," Tezuka answered. "That's going to be our lesson this Monday."

"Hmm." Fuji had that creepy smile on his face, just the kind of smile that warned others to back off, but compelled them to stay anyway and witness their own doom. Tezuka, feeling a little apprehensive, went to the kitchen to prepare some food. When he returned, Fuji was browsing his notebooks and chuckling amusedly to himself.

"You're a scary note-taker, Tezuka," he commented.

Tezuka ignored the comment. He sat down across Fuji. "Open your textbook. Page 58."

"Now you sound like Yamada-sensei…" Fuji giggled. "No wonder Taka-san's father mistakes you for a coach."

"Are you here to study, or do you want to run laps?" Tezuka warned. Hell, his patience hardly ever held long whenever Fuji was alone with him.

And it didn't help that he couldn't stop gazing (surreptitiously, of course) at the tensai.

"Tezuka," Fuji said, "I didn't bring my textbook."

Tezuka gritted his teeth. "You take mine; I've read it."

"Already? That's amazing, Tezuka, really amazing."

Tezuka ignored the comment once more. Fuji had sounded insincere. For all Tezuka knew, Fuji probably read his textbooks too. Why would he pass and top his exams?

"Okay," Tezuka began. "Let's start with action-at-a-distance forces. From the name itself, the force doesn't need to be in direct contact with the object. What's your weight?"

"Huh?"

"Your weight."

"The pull of gravity on me? It's a secret." Fuji smiled.

"You already know," Tezuka muttered. Since when had Fuji needed tutorials? He mentally scolded himself for falling in Fuji's trap.

"So, what's your weight?"

"Mine?"

"Yes."

"…You don't need to know."

Fuji chuckled, and Tezuka wondered if he'd said something wrong.

"Only gravity, or in the case of all things on Earth, weight, is the only action-at-a-distance force. There's another kind of fo—Fuji, are you listening?"

Fuji was eating, and noisily. "Mmm? Yeah, I am."

"…Okay. I'll continue." Tezuka picked up a length of string tied to a paperweight. "Can you tell me what forces are present in this?"

Fuji put aside the plate of food, studied the set-up, or pretended to. "Gravity."

"And?"

"I don't know." Fuji smiled again, and leaned towards Tezuka. "Teach me."

Tezuka didn't want to confirm that he'd heard something suggestive in Fuji's tone. "There's tension in this set-up. You say there's gravity. But if there's just gravity then the paperweight should be pulled back down to Earth, right?"

"I guess so." And now Fuji was gazing openly at Tezuka.

Tezuka's cheeks flushed; he suddenly wanted to turn away. "So…" he continued, "if the paperweight is still in mid-air, something must be pulling it up. That's tension." He pulled the string for emphasis.

Fuji nodded, still not taking his eyes off Tezuka (Or was it just his imagination? Fuji's eyes were closed most of the time, like now). He reached out to touch the string, fingers brushing against Tezuka's. Tezuka instantly removed his hand.

"And there's also the force of a spring, force of the air, but air only matters when the object is airborne; force of water, normal force, which is the force exerted upward by the surface, force of…" Tezuka's voice trailed off as he saw the last phrase written in his notes. "Force of…man."

"Ah!"

He knew why Fuji was suddenly interested in what he had to say. "What kind of force is that?"

"It's the force exerted by a man on another."

The moment the words left his lips, he realized they were wrong.

For Fuji had suddenly leapt on him, on all fours, and pushed him down into the sofa. "Like this?" the tensai asked.

"Get off me Fuji, I warn you!" He tried to push the smaller one away.

"Hmmm…" Fuji bent down, resisting the force of Tezuka's pushes, began tracing circles on Tezuka's chest with his index finger. "Am I not applying a force, Tezuka?"

"…You are."

"And the sofa exerts a normal force on you."

What the hell?

Fuji knew about forces. Of course. Tezuka tried to sit up, but Fuji was exerting a bigger force on him, and he had no choice but to lie down. Or maybe he didn't really want to get up…

"Ne, gravity is pulling you down, Tezuka," Fuji said mischievously. "Want me to pull you up with tension?" His hand tugged at Tezuka's fly.

"No!" Tezuka swatted Fuji's hand away from his jeans. "Get off me, Fuji."

"I cannot." A wicked smile formed on Fuji's lips. "Air resistance. Gravity."

"I warn you for the last t—" The words were cut off quite abruptly when Fuji swooped down and began kissing him.

This was just the exact reason why Tezuka didn't want to invite Fuji over.

Because, truth be told, he liked being kissed by Fuji. He probably would go beyond kissing too, if he intentionally forgot himself.

"What kind of forces are they, Tezuka?" Fuji asked when he pulled away.

"Contact forces…" Tezuka whispered. "Contact." He pulled Fuji close, and kissed his throat.

"Contact, eh?"

And then Fuji was kissing him senseless. Tezuka's head swam with different sensations, mostly lust, and he was practically gasping for breath when their lips parted.

"You forgot something, Tezuka," Fuji said knowingly.

"What? No, I mentioned all…" Tezuka couldn't think straight, not after what Fuji just did to him. Weakly he pulled the tensai toward him, who did not resist.

"Friction."

Fuji was about to kiss him again when Tezuka stopped him.

"No," he said, "I don't want friction."

"What about this kind of friction, Tezuka?"

And Fuji's hand began traveling under his clothes, then lower, lower, lower…

"I suppose I can live with that," Tezuka answered.

-end-

A/N: Yay! Our physics exam is this week, so I thought I'd write something to help me remember. My first time with Perfect Pair; hope it turned out right. Reviews appreciated!