I wrote this pretty long ago, but I've cleaned it up and stuck it here because why not? Contains implied slash, but the rating is just for language that could be considered suggestive if you take it seriously. (Hint: don't take it seriously.) As always, feedback is welcomed and appreciated.

Clark was waiting in the cave when Bruce arrived. He looked on from atop the towering computer as the car roared through the icy waterfall, scattering crystalline drops explosively, and growled—and prowled—to a stop. It had always reminded him of some large, feral animal, but he still hadn't decided which one.

The top panels slid back, and Batman leapt out in a fluid, oft-practiced motion. A few snowflakes were still in the process of melting on his shoulders and cowl: either the vehicle had a terrible heating system, or the drive hadn't been long enough for it to matter.

Because Bruce was Bruce, he almost suspected the former.

"Jesus, Clark," Bruce snapped when he saw him. "What are you, five? Get down." He strode across the cave, cape billowing dramatically behind him.

Clark flashed him a guileless grin and swung his legs innocently off the edge. His heels bounced rhythmically against the servers, filling the cave with hollow clangs.

"I swear," Bruce growled as he tugged off his cowl, "you are the most childish, unrestrained—" He broke off with a hiss, staggering slightly as a hand flew to his ribs. The cowl clattered to the ground.

"Bruce." Clark was at his side in an instant, checking for broken bones and only partially satisfied when he didn't find any. "Bad day?"

"I'm fine." Bruce brushed him off irritably. "It's just a muscle spasm." He pulled the chair out from the desk and dropped into it with the ghost of a grimace, releasing his ribs to start tapping at the keyboard. Several screens sprang to life.

"You're in pain."

It wasn't the most tactful thing to say, even if it were true, and with Bruce already prickling, Clark expected instant and vehement denial.

Instead he got a shrug—and a wince—as Bruce magnified one screen and started scrolling through lists of numbers on the one below it.

"It's not serious. It'll go away on its own. What did you want?"

"How long will it take?"

"I can be done here in about twenty minutes. You're welcome to wait upstairs; I think Alfred's been doing some baking."

"I meant for it to go away."

Bruce shot him a flat glare that may or may not have had an eye-roll tacked on as he turned back to the computer. "Hard to say. Could be an hour. Could be more. Could be less."

"Isn't there anything you can do?"

"It's not so life-threatening that I can't wait it out, Clark. I have work to do."

"That means 'yes' in Batspeak," Clark pointed out lightly.

"If you're just going to be obnoxious and distracting," Bruce bit off, "you can leave."

"I only want to help."

"Well, you're not. And I'm fine."

Silence fell between them as Batman continued to work and scowl and Superman struggled to block out the sound of his clipped, shallow breathing.

Bruce was right: intercostal spasms were annoying, but hardly dangerous. He'd dealt with far worse, and he surely wouldn't appreciate Clark's efforts to relieve them. It wouldn't take much—he'd just slip his arms around him, pull him close, allow his warmth to soothe the tremors away...

"Would you stop that?" Bruce growled.

"Stop what?" Clark was reasonably sure he hadn't said any of that out loud.

"Stop looking at me like that." Never mind that Bruce had had his back to him this entire time.

"Like what?"

"Like you want to undress me."

Total impassivity was Batman's forte, but Clark could still appreciate it.

"Hmmm," he said, appreciatively.

"No."

"It's not a bad idea." Now that it had been suggested, and by Bruce, no less...

"It's a terrible idea."

"You would be more comfortable without the armor," Clark mused, stepping up behind the chair, just into Bruce's personal space. "More relaxed, more...approachable."

Bruce jerked as feather-light hands ghosted over his torso, but the titanium plates were already falling away, leaving him in the thin black undersuit.

"That's better." Clark's smile sidled into 'smirk' territory.

"Clark," Bruce warned, teeth gritted. "I'm busy."

"Work, work, work," Clark scoffed. He deliberately laid his hands on the black-clad shoulders, one finger at a time. "You never take a break." He dug his thumbs into the juncture of the trapezius and the deltoid, feeling the knots there. "Especially not when you need one." He leaned down and pressed a kiss behind Bruce's ear.

Bruce made a small noise halfway between irritation and pleasure that utterly failed as discouragement.

"Just a back rub," Clark breathed against his neck. "Loosen you up." His voice dropped lower along with his hands, fingers dragging down the paraspinals with almost agonizing slowness. "Drain away all of the tension."

"Damnit, Clark," Bruce ground out, maintaining his rigid posture. "Now is not the time."

Clark slid his hands back up Bruce's sides, running long fingers against his ribs, stopping when Bruce flinched.

"Found it," he whispered, and pressed hard into the spasming muscle.

Bruce gasped—more of a choked cough than anything—as his entire body seemed to arch around that one point of contact, white-knuckled fingers straining against the arms of the chair, eyes wide and jaw clenched—

Then, just as quickly, he relaxed again, slumping back into the chair with an air of great relief.

"What the hell was that?" he demanded, still slightly breathless.

"Friction massage," replied Clark neatly, straightening back up. "It's not supposed to hurt, but I haven't done it in a while. Sorry. I assume it helped, though?"

"Yeah." Bruce took a deep breath, seeming to savor it. "Yeah, surprisingly enough. Dare I ask how you learned that?"

"I don't know—dare you?"

"No," Bruce muttered after a thoughtful pause. "Already too many surprises tonight."

"Pity. I was hoping for another."

"Clark..."

"Oh, come on, Bruce," groaned the Man of Steel. "You're dying to know what Alfred's made. Let's go."

And if Batman had to be dragged away, well, it was for his own good.

Really.

Friction massage is a real thing, but I may have used some creative license. Done correctly, it produces an analgesic effect in an area of damaged or spasming muscle; done incorrectly, it hurts like hell. So don't try it at home. =)

Thank you for reading!