(Belated) TickleTober 2025 🎃
Day 21: New Discovery
lee!Peter, ler!Tony (MCU)
Word count: 3.4k
Summary: After patching him up for a mild injury, Tony accidentally discovers Peter’s ticklish. Now, Peter’s walking on eggshells around his mentor—who now knows of his dreaded weakness—while trying to convince him otherwise.
A/N: I know, I know, this is super late but I didn’t want to leave these prompts unfinished :( So prepare for a ridiculously late TkTober spam i guess lol TwT
Peter winced as he limped through the Avengers compound to his room. Earlier, he had stopped a gang of criminals who were holding hostages at the mall. He was successful, but ended up getting minor cuts and bruises as a result. Peter brushed it off, confident that his enhanced immune system was going to heal him in no time. All he needed was to sleep it off with a long nap.
However, he may have underestimated the extent of his injuries. His right knee ached with a pulsing pain, and his left side of ribs hurt just as badly. Every time he took a breath, a stinging pain shot through his ribs. It hurt to breathe, curl, and sit down, but Peter was certain (and stubborn) that all he needed was to rest. He’d be fixed up in no time.
He slowly shuffled towards his room, his tired body yearning for the comfort of his bed. When he finally made it to his room, he groaned through his teeth as he slowly stripped off his Spider-Man suit, changing into fuzzy pajamas. Even that action alone proved somewhat difficult as he had to twist his body around to avoid stretching his left side or putting pressure on his knee.
Finally changed, Peter winced again as he slowly lowered himself into bed. He breathed out a long sigh through his nose—wincing a little—as the warmth of his bed and fuzzy pjs calmed his senses.
Reaching out for his plushie, Peter pulled his Iron Teddy—a Build a Bear he made and dressed in an Iron Man costume right after he began his Stark internship—against his chest and let his eyelids droop.
Peter must’ve fallen asleep for a half hour because Tony suddenly barged into his room, ecstatic. “Hey, Pete!”
Peter jumped, startled, and bit down a wince when he saw who was in the room. “O-Oh! Hi, Mr. Stark. What brings you here?”
“I saw your hostage rescue situation on the news,” Tony said with a warm smile. “Rescuing people while taking down a group of bad guys all on your own? 100% success! You really are doing great living up to your friendly neighborhood Spider-Man gig.”
Peter’s whole face lit up at the compliment. Still lying against his pillow, he twiddled his thumbs timidly. “Ah, y’know, just trying to live up to the name…being a hero and all that. But I did learn from the best.” He shot his mentor a proud smile, and swore he saw Tony’s expression get a bit emotional for a second.
“I’m proud of you, Peter,” Tony stated like a prideful father. “You’re doing great. And now, I can’t wait to stick it to Cap and rub it in his face that my 15-year-old underoos is surpassing him! Watch out, Cap, you’ve got some serious competition here!”
Peter laughed at the joke, and instantly regretted it. He hissed through his teeth as that stabbing pain returned on his ribs.
Tony’s eyes were suddenly filled with concern. He took a seat on the bed. “Pete, are you okay? What happened?”
“Nggrhh…nothing,” Peter grunted, forcing a smile. “Just, y’know, being a friendly neighborhood Spider-Man doesn’t always guarantee I won’t wind up with injuries. But I’m totally fine, though. I think I just bruised my knee and stretched a muscle.”
Tony shook his head, unconvinced. “From the sounds of it, it doesn’t sound like you’re totally fine. Let me check you up so I can give you something for the pain. It might be serious.”
“Oh—um—no, that’s okay, Mr. Stark, I don’t—”
Peter didn’t have a chance to finish his sentence because his mentor suddenly scooped him up, and carefully cradled him. The spider teen squeaked in surprise, slightly squirming in his mentor’s hold. “Wait! This isn’t necessary, Mr. Stark! I mean, not that I don’t appreciate everything your do for me.”
“This is absolutely necessary, kiddo. Minor injury or not, an injury is still an injury. And trust me when I say that I know how these things can worsen if you brush them off for too long. At least let me check you up.”
“But—But—” Peter sighed, giving up. “All right.” He let himself be carried all the way to Tony’s lab, where he was then placed down on a medical table.
“All right, tell me what hurts and how much. Rate it on a scale from 1-10.”
“Um, well, my knee and left ribs. For my knee, I’d say…like a 6? 6.5? It hurts if I bend it or put pressure on it. As for ribs, an 8. If I inhale too deeply, it feels like my ribs are about to be spring locked.”
Tony nodded. “Okay, you said firstly your knee hurts. But where specifically?” He reached a hand out to gently squeeze around the knee. “Like, is it the muscle above your kneecap that hurts more? The bone, specifically? Or just your entire knee?”
Before Peter could answer, a high-pitched squeak suddenly ripped from his lips—but not a squeak of pain. His and Tony’s eyes widened at the reaction.
Tony’s face melted to concern again. “I’m sorry, did that hurt a lot? This might be more serious than I thought.”
“N-No, I’m okay,” Peter tried to keep his voice level. “Sorry. Just—startled me is all.” He hoped Tony wouldn’t find his reaction suspicious but unfortunately, the slight pink hue on his cheeks said otherwise.
Tony gently squeezed the teen’s kneecap again. “So does it hurt more up here? Or more down here?’
Peter bit his lip, trying to fight back the wobbly smile that was threatening to spread across his face. “UmMMHMmhmhh..!” He tried to keep his leg still, but couldn’t stop it from twitching and jerking at every touch.
“Kid, you’re moving around too much,” stated Tony bluntly, not taking the hint. “I’m starting to think you could’ve sprained your knee, or worse. Let me check your ribs real quick.”
Oh no.
Forcing a smile through gritted teeth, Peter rolled on his side and sat up. “Um, that’s okay. I think I’m just being too dramatic. I’ll be okay; I’ll just take some Tylenol and sleep it off.” He was about to slide off the table, but his mentor pushed him to lay back down.
“Oh, no, no, no. I’m not letting you go anywhere with your clearly bad injuries. Let me inspect you so I can help, Pete.”
“But—aaAAH!” Peter couldn’t stop the little shriek he emitted when Stark gingerly prodded at his ribs.
“See? You’re worrying me even more, kid. You’re clearly not fine. Now, just hold still!”
“N-NoHO wAHAhait! AAAH!” Peter squirmed in place, groans mixed with giggles as his own reactions were causing his ribs to ache again. He tried biting his lip to prevent himself from laughing, but ended up snorting through his nose. Now filled with embarrassment, he sunk against the table and draped an arm over his face.
“Just stohohop…” Peter giggle-whined, shielding his ribcage with his free arm. “You’re not helping, Mr. Stark!”
Said billionaire sighed. “Peter, you don’t have to put up this ‘tough guy’ act all the time. You may be a kid with incredible powers—an Avenger, even—but even you aren’t invincible. You trust me, right? Now, why won’t you let me help y—”
Tony’s words caught in his throat when he noticed his kid’s behavior. His cheeks were dusted pink, his lips were curled in a wobbly smile, and he was guarding his ribcage like his life depended on it. And he flinched every time he touched the boy’s knee and ribs.
“Wait a second—pause. You were so jumpy back there because that tickled you, right?” Tony thought out loud.
Peter paled. “U-Uhm…no..?” he shyly replied in the most unconvincing manner.
Tony fondly chuckled to himself. “Why didn’t I realize this earlier? No wonder you don’t want me to touch you. You’re just really ticklish and afraid I’m gonna getcha, huh?”
“No! No, I’m not, okay?!” Realizing how he raised his voice, Peter cleared his throat and calmly recreated, “I mean, no. I’m not t—um…physically sensitive. These injuries just hurt and feel really uncomfortable, and I’d really appreciate it if you fixed me up quickly now.”
Keeping a straight face, Stark nodded understandingly. “Of course. I still need to see the extent of your injuries but since you can’t keep still, I’ll just do a bio-scan. FRIDAY, scan Peter for any injuries and tell me the extent of them.”
After the scan was complete, FRIDAY announced that Peter had not only pulled a muscle in his knee, but he also had a bruised rib.
“No wonder you were limping when you were trying to sneak-crawl your way back in through the window.”
Peter’s eyes widened. “H-How did you know that? Were you—were you spying on me?!”
“Kid, I have security cameras everywhere. Even in the refrigerator,” Tony bluntly answered. “But back to you; let me take care of that right away.”
After patching up his beloved mentee, Peter got up off the table and stretched. “Oh, wow. I feel so much better now. Thanks, Mr. Stark!”
Tony nodded with a relieved smile. “Anytime, kid.” He affectionately squeezed Peter’s shoulder near his collarbone, but immediately pulled away when the teen flinched with another sharp squeak.
“Geez,” chuckled Tony, shaking his head, “how ticklish are you? I can’t even pat you on the shoulder without you jumping out of your skin and squeaking like a mouse.” Peter flushed at his comment. “Aw, relax, Peter. I’m just kidding. But don’t think I’m going to drop this. I swear, this may be the best discovery I’ve made since finding out I can make popcorn with my arc reactor.”
Peter opened his mouth to object, but was silenced when his mentor ruffled his hair and walked away like nothing happened. What did he mean by ‘I’m not going to drop this’?
He shuddered at the dreaded realization: Tony Stark, his beloved mentor and idol, just discovered that he’s deathly ticklish.
Yup. He was toast.
The following day, Peter was on high alert. He had an uneasy feeling Mr. Stark was going to exploit his newfound weakness.
All day long, Peter was borderline paranoid. Every time he sensed someone walking behind him, he spun around with a yelp only to be half-relieved it was just one of the other fellow Avengers who were side-eyeing him at his weird outburst. And every time Tony came up to him, he flinched at each shoulder touch and side hug. He could practically feel his mentor’s fingers expertly prodding and pinching at his sides, except nothing happened.
By the end of the day, Peter was convinced he had been worrying for nothing. Tony didn’t try to tickle him once at any point during the day.
Breathing a sigh of relief in his room, Peter happily changed back into his fuzzy pajamas for the night. He was halfway through pulling his pajama shirt over his head when Tony suddenly barged into his room unexpectedly.
“Heyyyy, Peter!”
“Aaaaughh!” Peter shrieked in surprise and—still blindfolded by his own shirt—scrambled backwards onto his bed.
Tony laughed at the kid’s reaction. “Stuck in your own shirt? Here, lemme help you.”
“Nononono, don’t try anything! You better not!” Peter’s muffled voice came from under the soft fabric. He frantically twisted in place until his head finally popped out. He quickly held his hands out in defense. “Don’t…Don’t try anything funny. I know what you’re up to, Mr. Stark! What you’ve been plotting this whole time!”
Tony cocked his head to the side. “Plotting? Plotting what?”
“This while secret plot to get me after you found out I was t—mmghhh…ti—y’know—t-ticklish…And now, you wanna get me for reals! That’s why you’ve been sneaking around all day, acting all innocent, trying to catch me off guard so when I least expect it, you can get me! Well, your tricks won’t work on me! Even if they are devilishly clever!”
“Is that what all this paranoia is about?” Stark shook his head. “Kid, I was never plotting to get ya. I only teased you yesterday because I thought it was adorable the way you reacted over a couple squeezes and prods.” He took a step forward, making Peter shrink back. “But since you suggested I take advantage of the discovery that you’re super ticklish, I say that’s an excellent idea!”
Uh-oh. Oh, no. No, no, no, no, crap! I have got to stop suggesting things like that out loud!
“Y’know, you really shouldn’t suggest things like that out loud if you ever encounter a villain who finds out your little weakness,” continued Tony. He saw Peter’s gaze eye his web shooters on the nearby nightstand in debate. “Try it, and you’re getting tickled nonstop for an hour.” Peter then eyed the door behind the billionaire—his only escape. “Try that or jumping out the window, and I’m bringing the rest of the Avengers to tickle you silly for the rest of the night.”
“Noooo, Mr. Staaaark! You’re so meeeeean!” the spider teen whined like a child. He squeaked and backed away as much as he could when the older Avenger made a grab for him. “NoAAAHAhoho!!” As a last result, Peter threw his Iron Teddy at his mentor’s face, who swiftly ducked.
Tony raised a playful brow. “Ohh, so that’s how it’s going to be?” he asked in a playful tone. “Alright, c’mere!”
“Nooooo!”
Peter squealed as he was grabbed and pulled into his mentor’s arms. Tony took a seat on the bed, effectively securing the teen in his arms. He wasted no time and repeatedly tased Peter’s sides.
Instantly, Peter burst into squeaky giggling. He batted at his mentor’s hands, which in turn got him a couple warning scritches to his belly.
Peter squawked and curled inward as much as he could. “WaHAHAhait! Wait, Mihihister StAHAHAhark!! W-Why ahahahare y—EHEAHA—you doihihihing—?!”
“Why am I doing this to you?” Tony interrupted the giggly teen. He slowed his fingers down a tad to little sporadic pokes up and down Peter’s sides. “Well, two reasons. One: you tried to sneak into the Avengers compound and thought you were so slick with it. Second: this is just absolutely adorable, and I can’t believe you thought you could hide this from me! Win-win if you ask me!”
“WhAHAHAhahat?! H-Hohohow is thIHIHis a wiHIHIhin?! You’re juhust doiHIHIhing this to be mEHEEHEEhean!”
“Calling me mean now?” Tony pretended to sound offended.
“W-Wait, wait, I take it back! I-I take it—bAHAHAEHEHAHA! NOAHAHAHAHA!!” Peter couldn’t finish his sentence because Tony brought both hands upward to quickly scribble against both sides of his neck. “WAHAHEHEHE!! WaHAHAHAIT!!”
“Oh, fine, you little whiner.”
Peter breathed a giggly sigh of relief as the scribbling fingers stopped. However, exactly three seconds later, he shrieked with screechy laughter again when Tony went back to scribbling his belly. “AaAAAHEHEHEHAHAHAAAA!! H-HeHEHEY! MIHIHIster StAHAHARK!?”
“What? You never said how long you wanted me to stop,” Tony answered with a shit-eating grin.
“AAAHEHEHE! B-Buhut thAHAhat’s not faHAHAHAHAIR!!”
Tony hummed unsympathetically, “Mmm, life’s not fair, kid. You know what life often is?”
“WHAHAHAHAHAT?!”
“Unfair.”
Tony burrowed his wiggling fingers deeper into the folds of Peter’s thick, fuzzy pajama shirt. Based on Peter’s adorable screechy reactions, he guessed he must’ve hit a good spot. But he wasn’t done yet. He paused the playful attack for a moment.
“I gotta ask, because you’ve got me intrigued, where else do you happen to be ticklish? Because this is absolutely adorable! I don’t think I’ve heard you genuinely laugh, Peter.”
Peter hid his already red face behind his pajama sleeves. He shook his head in response. “N-Nowhehehehere!”
“Don’t you lie to me, kid. You’ve already done that twice tonight. Do you really wanna lie to my face and make this worse for yourself?” Tony emphasized with a quick tase to the sides.
“EHEEP! But I’m nohot even ticklish..!” came the giggly teen’s muffled reply.
“Kid, I know you’re blushing under there. I can see how red you’re getting; you look like your suit’s color. Don’t make me squeeze it out of you.” Tony rested his fingers on Peter’s belly as a warning.
Slowly, Peter revealed his blushy face. Tilting his head up, he flashed the most innocent-looking puppy eyes he could muster and said, “I’m telling the truth, Mr. Stark! I’m really not ticklish. The only reason why I’m ‘reacting’ as you say is because you’re catching me off guard, and startling me—EEEEHEEHEEHEE!!”
Tony heard enough, going back to scratching at Peter’s tummy like a puppy. “Alright, I think I’ve heard enough. The hard way it is, then.” He tapped into his comm link, alerting the rest of the Avengers. “Nice knowing you, Peter. Avengers, could you come over to my location, stat? We’ve got a little situation that needs—”
“OkAHAHAY! O-OKAHAHAY!!” Peter blurted out in a panic. “I-I’m ticklish, okay?! So ticklish! I-I lihihihied ‘cause I dihidn’t want you to find out and then start teheeheeheasing me about it forever! And ‘cause it’s sohoho embahahaharrassing!”
Tony hovered above him, grinning down. “I knew it. I just wanted to hear you admit it out loud. I wonder though if having your senses heightened from the spider bite also amplified your ticklishness? Or better yet, made all the general ticklish spots twice as sensitive?”
Instead of answering, Peter attempted to make a run for it by wriggling out of his mentor’s arms. He couldn’t get so much as two steps before his knees gave out beneath him and he face-planted against the floor in a heap of giggles.
The billionaire chuckled. “Well, well, looks like when you get flustered, it makes you all loopy. And renders you vulnerable. Good to know for future reference.”
Peter flipped onto his back and with a wobbly smile, aimed his web shooters at the Avenger.
Stark raised a brow, both amused and impressed that the kid dared to challenge him like that. “You web me, and I will call the others to come and help me. I’m serious.”
“And I’m serious that I’m not spilling where I may or may not be theoretically ticklish!”
“Last chance, Peter,” Tony said with a sinister grin. He hovered over the teen with menacing wiggling fingers like a super villain.
Still on a giggle-high, Peter cheekily stuck his tongue out in response.
“Okay, now you’re just asking for it! C’mere!”
Peter squealed adorably as he was once again restrained in his mentor’s arms. And this time, Tony was no longer playing nice as he thoroughly tickled him on each and every possible tickle spot Tony could think of.
As if that wasn’t bad enough, Peter’s screechy reactions not only completely gave him away, but his fuzzy pajama shirt couldn’t protect him from the vicious raspberry assault Tony gave him in the end. To Tony, that was the most cutest reaction he had ever seen (even if it did feel like his eardrums shattered from how shrill Peter’s scream sounded). But to Peter, it was easily the most embarrassing thing that could ever happen to him.
Now, his mentor whom he looked up to knew how and where he was ticklish, but also knew the quickest way to kill him was a big raspberry right to the center of his tummy.
By the end of it, Peter lay like a limp starfish. His face was tomato red and his hair looked like a bird’s nest. Tony just laughed and bent down to ruffle his hair. “Maybe that’ll teach you to think twice before you lie to the great Tony Stark. I always find out the Avengers’ secrets. But, look at the bright side, Pete. Now we know how to cheer you up whenever you go all ‘moody, sulking teenager’ on us.”
Peter shot his head up, eyes wide. “‘We?!’ What do you mean by ‘we?’”
Instead of answering, Tony just stood up with a sly smile. He slowly walked backwards towards the door. “Get some sleep, kiddo. I’d sleep with the door locked if I were you. Y’know…just in case.” He winked, then shut the door.
Peter laid frozen on the floor for a few seconds, trying to register what he was just told. When he finally stood up, he fixed his pajama shirt, climbed into bed, and decided he’d do more than just lock his door shut that night; he webbed the entire door from top to bottom so no one, especially Tony Stark, could try and tickle him in the middle of the night.
So much for keeping his dreaded weakness a secret…
THE END
