"I could destroy that machine if I wanted to."

Bruce looked up warily from his invention. He was following the blueprints left behind by his older self, to build the time machine that would take him home. There was some form of progress standing on the table, with a similar base as his older self had managed.

"Go ahead." Bruce pulled down his goggles and refocused on the welding. "I'll deep fry you for dinner."

Clark placed two cups of coffee on Bruce's workspace. "It's very delicate, isn't it?"

"Batman's time machine. Thought up by a man with thirty more years worth of knowledge and experience." Bruce scowled, tracing the drawing with his finger. "What do you think?"

"Looks high-tech."

"Don't touch it with your dirty hands."

"I just washed them. With detergent." Clark said defensively.

"By dirty I mean wet." Bruce glared at him through the white dancing sparks. "No sex for three months if you dare get one water molecule onto my stuff."

"That amount of time is all I'm gonna get, and you're going to threaten me with that?"

"Did you come to distract me, or threaten me?"

"I came to say I love you, I miss you, I can't live without you, and I'm going to let you go."

Bruce cocked an eyebrow at him. "Last two phrases. Very contradicting."

"I love you and I want you to have a happy future." Clark smiled at him. "It wouldn't be right if I forced you to stay here with me, would it?"

"At least you know so." Bruce continued attaching some colorful wires. "When did you reach that conclusion?"

"Some time in the last three months."

"Broad."

"Well," Clark sat himself down at the opposite end of the table. "When did you reach the conclusion that you wanted to have sex with me?"

"Some time during that family dinner." Bruce replied instantly.

"Oh." Clark's eyebrows furrowed. "Disturbing."

"My mind works simultaneously on several levels." Bruce retorted pointedly.

"Right. So there's level one, maintaining civilized conversation with Tim and Barbara. Level two, defending pumpkin soup against Dick and Jason. Level three, working out the implications of Bruce Wayne's altered time travel machine. And level four, how to seduce the distressed Kryptonian after throwing him a bottle of antidepressants at the speed of a pistol bullet."

"Correct." Bruce answered nonchalantly, sparing him no attention.

Clark rested his cheek on his palm and watched Bruce work. His steaming coffee remained untouched, but Clark didn't mind. Bruce concentrating on his work was a lovely sight.

"How long are you from finishing your machine?"

Bruce retraced his drawings from top to bottom. "Three months, give or take. When the last hummingbird leaves Kansas, I suppose."

"What's that weird fascination with hummingbirds?"

"I came with them, when they flocked onto your fields. It's only logical that I leave with them."

"Bruce Wayne, spouting teenage romance novels while inventing a time machine."

"Building." Bruce corrected him. "I didn't invent it."

"Bruce Wayne, spouting teenage romance novels while building the time machine that Bruce Wayne invented. How's that?"

"That's better. Except it's adult."

"Oh I don't think that qualifies as-" Okay. Bruce managed to shove him off his chair, his equipment forgotten. Then his hands were roaming across Clark's chest. Clark felt Bruce's fingers attempting to pull down his zipper.

"That's porn."

"Porn with plot. Adult romance novels." Bruce whispered into his ear, his voice seductively low. "What did you think people are selling on the market these days?"

"Nothing involving sex next to a giant unfinished time machine that might get squashed by a super powered alien, which might banish us to God knows where."

Bruce rolled his eyes. "Fine, scoot two feet farther from here. And don't electrocute me."

"Roger that."

They were halfway through rubbing their cocks together when Clark sat up with sudden clarity.

"Fuck, don't stop-" Bruce moaned, still thrusting wantonly against Clark's hips.

"Damian and Alfred-" Clark warned belatedly. At the same moment the door to the Batcave opened and Clark swept them under the table.

Bruce jolted up, his head half an inch from hitting the underside of his desk. It was Clark's hand that cushioned that hit, but the alien's palm was little better than metal.

"Ow, fuck!" Bruce whispered, low enough that only Clark could hear. He curled up cautiously and rubbed the back of his head.

"Sorry." Clark grinned sheepishly.

"-should not be creating this machine." Damian's sharp voice shot across the cave.

"-is solely Master Bruce's decision." Alfred's calm voice countered. There were rhythmic sounds of metal on ground that was his walking cane tapping by his side. His wheelchair lasted not a month after Bruce's return. He was now capable of walking down the damp slippery grounds of the Batcave.

"-deserves to retake the mantle of Batman."

Bruce bit back his retort, his willpower solely from the fact that he was naked from the waist down. Clark's breath was still at his ear, his hand slowly pumping Bruce's cock. The both of them, half-naked and hiding under the table. Bruce panting and trying not to moan.

"Looks like I'm not the only one who wants you to stay." Clark whispered into his ear. He dragged his hand down Bruce's length with just the right amount of pressure. Bruce's tortured exhale was enough encouragement.

"I'm going to have a long talk with Damian tonight." Bruce gritted his teeth. He spoke at a volume that only super hearing could discern.

"Why not now?" Clark asked teasingly. Before Bruce could complain, he lowered himself on Bruce's cock. Then he was sucking Bruce in the little space that they had, twirling his tongue around the spongy tip. Drawing out the salty bitterness that was Bruce's unique taste.

"Jesus Christ-" If Bruce wanted to kick him away, his motivation was shattered the moment Clark's wet mouth engulfed his throbbing erection. Nevertheless he did his best to scoot away from him. Wrong move. A second later he heard the loud clang of his elbow hitting the side of his desk. Clark almost spluttered.

The silence from behind the half-finished machine was staggering. Bruce dared not breathe.

"What was that?" Damian's voice was suspicious.

Bruce was using every known language to curse the alien sitting beside him. Clark's face was still unbelievably smug.

"There are always bats in a Batcave, Sir. Animals can't refrain from moving. Some might have crashed into your father's equipment." Alfred explained, his voice deadpan. "Now if you'll excuse me, I have to prepare for dinner."

"I will discuss the matter with Father when he returns." Damian said resolutely. He stepped past the threshold without looking back. "And I want marshmallows in my hot chocolate, Pennyworth."

"Of course, Master Damian." Alfred took one last glance at the Batcave before shutting the door.

The moment the lock clicked, Bruce scrambled up from under the desk. "You insufferable, shameless, thoughtless-"

For a moment he couldn't read Clark's face, and there was no movement following him. Then Bruce bent down to look, only to find the alien curled up. He was clutching his abdomen, resisting the overwhelming urge to laugh. "Sorry," Clark managed when Bruce's glare reached him a second time. "I couldn't throw away that opportunity."

"My older self managed sixty years without ruining his image of being a good father and son. I almost ruined it in three months, because of you."

"Your definition of being a good father and son is not having sex?"

"Having sex behind closed doors and not blinding my family with inappropriate carnal behaviors."

"I'm sure Alfred had a very good idea of what was going on with or without the safety of a concrete wall."

"Get out before you break my desk." Bruce growled.

"Come on, you enjoyed it." Clark climbed out of the cramped space and stretched. "Still horny?"

"Very." Bruce pulled his pants up and tugged his erection back into his underpants. "My bedroom exists for a purpose."

"Sure." Clark did the same. He was still wearing a silly smile, like a kindergartener who got away with eating chocolate in class.

"How's the world of rainbows and butterflies?" Bruce asked casually with his back facing Clark.

"Pardon?"

"You look happy." Bruce said, turning back to him. "Either that medication is working, or you're easing back into positivity. It's… endearing. That smile on your face." He only looked away when he spoke the last phrase.

For a long moment, Clark stood, finally feeling each movement of his facial muscles in his full awareness. Then he smiled again. It wasn't that hard, wasn't that daunting to pull off naturally. "I never could have done it without you." He admitted earnestly.

"Keep it up, Clark." Bruce flung a cardigan over his shoulder and headed for the stairs. "You need it more than I do."