Disclaimer: The characters are not mine. I'm not that awesome.

Tony Stark entered S.H.I.E.L.D.'s well-equipped gym to find Steve in his usual place beside the punching bag, striking at it as if he thought that in doing so, he could release all of his anger at the men who had released him from his frozen prison, seventy years out of his own time. Hell, that's probably what he was aiming for.

"You know what I don't get, Cap?" Tony asked, startling Steve who hadn't noticed his arrival.

"What's that?"

"Why you come down here day after day, for hours on end. Seems to me you're as strong as ever and if you keep going like this, you're going to be worn up by the time we need you."

"Because, Tony, unlike you I can't just sit around waiting for something to happen. I need to keep busy and working out is the only thing I've found since I was brought here that keeps my mind off of things." He was, of course, thinking of Peggy and the rest of his friends and family left behind when he disappeared all those years before. Most of them we dead by now, he had come to terms with that, but he still found himself feeling more depressed than he had ever felt in his life. The only way he knew how to cope was just to try and forget about it.

"Oh," was Tony's response, "I thought you came down here because you were trying to remain big and macho since that's really the thing you've got going for you. Well, that and your weird shield."

Now Steve was mad. Sure, he might not be a trained assassin like Natasha or Clint, and he may not be able to fly or shoot lasers like Iron Man here, but dammit, he had something to contribute. They wouldn't have brought him back otherwise. Glaring at Tony, he took a deep breath to try and release his building tension and turned back to continue his training.

"You know, we don't even really need your strength. We've got Bruce for that and you can bet he's ten times stronger than you are when he's in rage-form."

Steve turned back to look at Tony, the anger resurfacing. "Why are you doing this?"

"For fun. Sometimes I like to push people, see how much I can anger them before they snap."

"And what makes you think this won't cause you harm in the long run?"

"Oh, you wouldn't hurt me, Cap. You've got too much character." With that Tony grinned and walked further into the gym. Circling the weights, acting like he was examining them when really he was just waiting for Steve's response.

What he'd said was true. Steve did have far too much kindness in him to think about hurting another person, even one who could be as annoying as Tony. Sighing again, Steve didn't respond but went back to taking his aggression out on the punching bag hanging before him.

"Do you know what else I don't understand?"

"Stark, it might be in your best interest to leave. Now."

Tony kept going as if Steve hadn't said anything, "Why isn't tickling used in combat?"

That stopped Steve mid-swing. Tickling? Was he serious? "Tony, this is war we're talking about. With grown men. Not children on the playground."

"Age doesn't play a part in this, Cap. If you're ticklish you're ticklish and most people are."

"And what? You think tickling would work up against a fully armed army?"

"No. But in hand-to-hand combat I think it could be a non-violent way to take down an enemy."

"You think…no. I'm not going to be drawn into this." With that Steve turned back to the punching bag.

Tony continued circling the gym, unnoticed by Captain America. Finally, he ended up directly behind him.

"Don't."

"Don't what?"

"Whatever it is you're planning to do, do-hon't!"

Still behind him, Tony stood with his right hand just inches from where he had prodded Steve's side. "See? Just proving my theory. Most of us are ticklish, Rogers. Catch someone off guard and they could be left completely defenseless.

Angered that he had let himself be caught, Steve spoke heatedly. "Tony, I highly doubt that in the heat of battle-Hey! Stop that!"

Steve suddenly found himself fighting a full-on assault of Tony's fingers trying to dig themselves into his ribs. He couldn't help but feel ashamed as he noticed himself retreating backwards in an attempt to get away and stopped himself, choosing to make a grab at Tony's hands instead. It wasn't hard.

"See, Tony? There is a flaw in your plan. While it might be true that a person can be made momentarily defenseless, all it takes is a moment of focus to render you incapable of attack."

Tony, his wrists locked firm in Steve's strong hands, took the Captain's moment of relief and with his left foot, swept Steve's feet out from under him. Pulled down with him, he found Steve's grip momentarily loosened and pulled his hands free. As the Captain struggled to realize what it was that had just happened, Tony straddled his waist and grabbed his hands with his own, pinning them above Steve's head.

"What the hell was that?"

"It strikes me that you don't enjoy yourself enough, Cap. You take things way too seriously."

"We've already established this doesn't work, Tony. I was nice last time, I could have done worse than just grab your wrists. I won't make that mistake again."

Tony grinned, "Sounds fun. Right now you're at the disadvantage, though." He leaned forward so he could hold both of Steve's wrists under one forearm, waggling the fingers of his other hand in front of Steve's eyes, taunting him.

"Now tell me, where are you ticklish?"

Steve was gritting his teeth now. He was angry, that was for sure, but he was also nervous. "Tony, just don't. Get off of me and leave. Now."

"I don't think so. Now, you could tell me where you're most ticklish and save yourself my fingers prodding all over your body, or you can try and remain your tough, stoic self leading to your eventual break when I inevitably hit a sensitive spot. After all, I already know where one of them is." He demonstrated this by wiggling his free hand in the side of Steve that he had touched upon before, causing Steve to inhale sharply and shift underneath him.

"Not gonna tell me? Okay, this will be more fun anyhow."

Before Steve could get another word in, he was laughing uncontrollably as Tony dug his fingers into the hollow under his arm, first stroking softly but then escalating to a faster irritating scratch, not changing pace or pressure, just hitting the same spots over and over again. He jerked his body up and down, trying to throw Tony off but it was no use. While he was laughing like this he couldn't get his strength to work for him.

"Wow! I knew I could get you to laugh but in all honesty, I didn't expect to win this one. I didn't know anyone could be this ticklish, let alone America's oldest superhero. Imagine if your enemies got a hold of this information."

"To-hony! Please! Stahahap!"

"Can't do that, soldier. It's good to hear you laugh. Who knows when it'll happen again?"

Tony shifted his weight a bit lower, slightly loosening his control of Steve's wrists, to focus his attention on his ribs and stomach.

"What about here, Steve?" he asked, wiggling a couple of fingers underneath his squirming captive's ribs. "Is that better or worse than the armpit?"

Steve yelped and began to buck harder. "Tony! Stop! I c-can't take anymore!"

Tony had been scribbling his figures softly across Steve's stomach, prodding at his hips every few seconds but now stopped, allowing the poor man beneath him to catch his breath.

"What can I say, Rogers? Every man has his weakness. And now I know what yours is." Still sitting atop the gasping soldier, Tony smiled sheepishly at how red Steve's face had become, making his blonde hair stand out.

"The only…problem…with your plan," Steve said, in between deep breaths, "is that revenge…is so easy."

With that Steve grabbed both of Tony's hands in one of his own and flipped the startled man to his back, switching positions with him.

"Really? Are you going to resort to something so childish as this? Captain America, tickling another man. Never thought I'd see the day."

"It's not going to work, Stark. I can see right through your tough guy attitude. As for me tickling you, fight fire with fire, right?"

Now Steve was reflecting the patented Stark grin. He had noted the change in Tony's eyes from confident to nervous, had felt Tony's breath begin to quicken, and knew he was going to have fun with this.

"Maybe you're right. Maybe this," he held up his free hand, wiggling his fingers the way Tony had at him only minutes before, "is the key to winning wars."

"It won't work," Tony gulped, a slight tremor in his voice betraying his nerves. "I'm not even ticklish."

"Ha! Sure you're not. In that case, I'm not either." He placed his hand on Tony's ribcage. Not tickling, just to see if he could make the billionaire any tenser. It worked. Steve was smiling outright now.

"I'm a lot stronger than you are, too. I doubt you could get away no matter how hard you tried. And don't think I can't feel you struggling already. Muscles tensed. Starting to squirm. I haven't even started yet."

"Alright, that's enough. I swear, Steve, if I had my suit right now we wouldn't even be having this discussion."

Now Steve was laughing, "Ha! I suppose that's really all you are, isn't it? Just a man in a metal suit. Well, unfortunately you don't have your suit right now. In fact, you're pretty exposed," he shifted his hand from Tony's ribcage to the base of his shirt, his fingers just grazing the skin underneath. "I could make this go on for hours, too. Probably should if I want to make sure you learn something from this."

Tony was now struggling harder, trying desperately to break free from the super-soldier's grasp. "Steve, don't."

"Just remember, buddy, you started it."

Tony felt Steve's fingers tense and quickly grasp his side right above the hip, causing him to jolt and gasp. Then, surprisingly, he was released. Steve got off of him and stood up, offering Tony a hand in turn.

"Wha-what are you doing? Is this some kind of trick?"

"No trick, Stark. I'm letting you off this time. Remember what I said, though. I can have you back on the ground in a matter of seconds and next time I promise you I won't be feeling so kind. If I were you, I'd stay out of my way for awhile."

His heart still racing from the adrenaline, Tony grasped the hand offered to him and Steve helped him off the ground.

"Well, thanks…I guess."

As Tony quickly exited the room Steve smiled again. If he knew Tony at all, he wouldn't leave him alone for too long.