Peter hadn't ever really thought about it.
Thanks to his tendency to web up crooks and villains, there were a hundred different bondage jokes floating around about him in YouTube comments, but it wasn't something he paid attention to any more than the cannibalism and vore jokes about him and Black Widow. He'd beaten up any number of people, but it wasn't like that.
The only time he'd popped an inappropriate boner when engaged in violence, it was a friendly spar, and Peter would dare anyone not to react when they had Tony Stark spread out underneath them, hips rolling as he tried to buck them off. It was unavoidable and inevitable, okay? It was a matter of friction and general attraction, not how sexy Tony looked when he was sporting a red mark on his jaw that was almost certainly going to bruise or the heady rush of power that came from putting Tony in his place (under Peter) and keeping him there. And Peter had certainly never had a thing about collars or putting Tony in one.
Then Tony had gone and gotten himself kidnapped and—well.
What Peter focused on first was that Tony was okay: alive, reasonably well, and kind of pissed off. They got him outside and into the back of a sedan FRIDAY had driven there, though he'd only gotten as far as sitting sideways on the bench, legs sticking out of the car, before insisting that no, he wasn't going to the hospital, and he certainly wasn't going home like this.
"I can't believe none of them had a key. Who puts a collar on someone and misplaces the key?" Tony tugged at the metal around his neck, which resulted in it digging into his skin on one side and revealing the delicious red where it had chafed on the other. "That's almost as stupid as leaving me alone in a workshop after threatening me. They should've asked the last guys how well that worked out for them, except oh, wait, they're all dead."
Peter placed a hand over Tony's and pulled it gently away from the collar. "Good thing for you, huh?"
Tony smiled, lopsided, but present. It pulled at the split in his lip. "I knew you were coming for me. If nothing else, Rhodey was going to tear this place apart the second my transponder activated."
Rhodey was currently doing so along with Vision, because no one was willing to take a blow torch to the metal loop around Tony's neck, and there had to be a key somewhere, even if none of Tony's captors had been willing or able to cough it up for Tony himself. Which left Peter with Tony as Peter grew more and more uncomfortably aware with every passing second of details beyond "Tony was okay."
Details like the bruise kissing Tony's cheek and the almost artful trail of blood running from Tony's scalp down his face, along his neck, passing under the steel collar and disappearing into the black cotton of his t-shirt. Details like the abrasions on Tony's knuckles and the small burn on his wrist. Details like Tony's split lip and the sudden and piercing realization that Peter would really like to kiss it, to worry it between his own teeth until it started bleeding again.
"Huh," Tony said, looking up at Peter with a suddenly considering expression, like he'd turned a puzzle around and figured out the missing piece.
"What?" Peter asked. He rubbed his thumbs gently over Tony's palm, not quite a massage, but a little more than handholding.
"You're into this. The collared kidnapping victim freshly rescued." Tony waved his free hand up and down his body. "This is a thing for you."
"What? No," Peter said, but his voice sounded unconvincing even to his own ears.
Tony was smiling again, wide, with unexpected delight. "You are." He leaned forward. "So I've gotta know. Is it the whole general aesthetic, blood and bruises are what get you going, or is it the rescue part? No judgment either way, but—"
"It's you," Peter interrupted in a rush. He dropped Tony's hand to rub at his own face, wishing he hadn't taken the mask off once they were alone. He felt entirely too exposed. "It's just—it's always you, Tony. The, uh, the rest is just, um. Extra."
"I can definitely work with that." Tony pulled at Peter's wrist. "Gonna have to help me out here. Freshly rescued kidnapping victim, remember? Lean down."
Peter thought, What? one last time, but he leaned down. Tony surged up to meet him. They kissed until the split in Tony's lip reopened, and then they kissed some more. They kissed until Rhodey came back out to say, "We're not finding the key, so could we please—" and then stopped abruptly as he actually caught sight of them.
Reluctantly, Peter straightened, separating their lips. When he licked his own, he tasted blood. Tony looked dazed, off-kilter. It was incredibly gratifying.
"You know, if you wanted a minute alone, you could've just asked instead of sending us on a wild goose chase." Rhodey sounded more resigned than annoyed.
"Rhodey, buddy, I'd really appreciate another minute alone with Peter here," Tony said.
"I'll go find Vision. But it really will be just a minute this time."
"Did you want to talk about this?" Tony asked.
Peter kissed him again.
"You're right. Talking's overrated." Tony kissed back.
Two weeks into dating Tony, he said, "I've got something for you."
Normally, when Tony said this, he meant he had a suit upgrade or something related to show Peter. He'd lead Peter to the workshop and show off a little. This time, he led Peter to his bedroom at the Compound.
"Is the something your dick?" Peter asked when Tony locked the door behind them and toed off his shoes.
"That, too." Tony flashed a grin. He walked to the bed, where two boxes waited. He picked them both up and shoved them at Peter. "Choose a set."
"It's not even my birthday," Peter said. He opened the first box. Inside was a leather collar and cuffs in dark brown. They looked butter soft. They felt that way, too. "These are for me?"
"Well, for you to put on me. We both know I'm getting something out of this, too."
"Do we?" Peter looked up at Tony. His lips were quirked like he was prepared to play it off as a joke. Peter's throat was tight. His face was hot. "Because, uh, I'm not going to lie, I'd be into it. But not if you're going with it to humor me."
Tony picked up the leather collar. His eyes were dark. "Maybe just the collar to start?" He tipped his chin up. "Put it on me?"
Peter put the boxes on the nightstand. He traced Tony's throat with his fingers, kissed his throat gently, and took the collar back from him. He threaded the tongue through the buckle, no locks here, and kept three fingers between the leather and Tony's skin to make sure there was plenty of slack. When Tony swallowed, Peter felt it against his knuckles. Peter tugged on the collar, pulling Tony into a kiss. Tony swayed forward, leaned into it.
"We should talk about this."
"Sure, we could talk about it," Tony said. "Or you could do what you want with my very enthusiastic consent right now."
Peter frowned. "You don't know what I want. There could be—I could want something you don't."
"Did you have in mind anything that would cause permanent damage?" Tony asked carefully. Peter's horror at the thought was apparent enough that Tony continued, cheerful again, "Then yes, I'm up for whatever. I have a whole trunk full of toys you could use on me, but I thought you might be more into using your bare hands. If you want to gag me, we'll need to work out some sort of signal for if it gets to be too much, and I don't want any fabric over my full face, but otherwise," Tony spread his hands, "feel free to surprise me."
Tony's confident expression faltered in the face of Peter's ongoing horror. "I thought—you seemed like you were interested in this."
Peter had done a little—a very little—research into how this was supposed to work when he'd realized his own interest, and he was pretty sure this was really, really not it. "Um. I'm very happy to have you in that collar, but if you want anything more, I think we really do need to talk about it first."
"Yeah, fine. Okay. We'll talk about it."
They talked about it, sitting at the foot of the bed.
Peter expected for there to be more lines drawn, for Tony to clarify that okay, yeah, not the face. Instead, he said, "That's what makeup's for," and, "If I need medical attention or have to get stitches, you get to explain why, but that's not a no."
"There has to—you have to have some sort of hard no."
"No fabric over my face, no water over my head, no electricity period," Tony ticked them all off on one hand. "Already told you the first, I'd have plenty of warning to say no if you wanted to try the second, and I don't keep anything on hand for the last. Oh, and no permanent damage, but we covered that, too."
"That's it?" Peter asked.
"That's it. Either of us can tap out at any time. I promise, if I don't like something, I'm more than capable of saying so." Tony's smile was wry. "But I think you'll find that there's not much you could want that I wouldn't be happy to give you." He held up a hand at Peter's automatic protest. "Not humoring you, just extremely flexible."
Peter wasn't sure he believed that. "So if I said I wanted to slap you around until you were as bruised and bleeding as a couple weeks ago—?"
"I'd say we need to find a ring or something, because open-handed just isn't going to cut it for drawing blood."
Peter put his face in his hands. "Is this, have you done this before?"
Tony placed a hand on Peter's shoulder. "Yes. But it's suddenly occurred to me," and his voice was even more careful than when he'd asked if Peter wanted to cause permanent damage, "that you might not have, and I just tried to drop you in the deep end."
"Tony, I don't even know how to swim."
"I'm happy to help you figure it out." Tony pressed a kiss to Peter's jaw. "Nothing would please me more."
Peter threaded his hand through Tony's hair. "I'm just. I don't want to hurt you."
"That's kind of the opposite of what I was expecting considering the bruised and bleeding thing, but pain doesn't have to be part of this if you don't want it to be."
"No. I mean. I don't want to hurt you."
Tony thumbed at Peter's lips. "So we'll work our way up. Want to start with pulling my hair?"
Yes, actually. Peter did.
Tony smiled at the first tug, then grinned at the first yank, offering no resistance at all, head tipped back and throat exposed, collar's buckle front and center. "That's good. Maybe a little harder, but not too much. Want to try slapping me around next?"
"Are you sure—?" Peter felt like just pulling Tony's hair was more than anyone could reasonably ask for. He was awed and overjoyed just to get to put his hands on Tony, much less do anything more.
"I'm very sure. I'd happily sign any waiver you put in front of me. C'mon. Hit me, Pete."
Peter's first attempt was more a pat against Tony's cheek, and Tony looked so disappointed, over-exaggerated and cartoonish, that Peter immediately tried again, a slap that rang out. Tony's cheek was a bright red, and there was something sharp and wild in his eyes.
"That's more like it. Give it to me again."
Peter did, evening out the color in Tony's cheeks. Tony's smile was fierce.
"How's that feel?" Tony asked.
"Shouldn't I be asking you that?"
"I asked first."
Peter stroked the red he'd caused. "I shouldn't like it this much."
"Fuck should." Tony leaned into Peter's hand. "I'm having a great time."
Peter kissed Tony, gentle, sweet, then bit Tony's lip. Tony made a sound that wasn't pain. Peter did it again. Tony tugged him forward, pulling him in and grinding their hips together. Peter could feel just how good of a time Tony was having.
Peter pulled Tony's head back and sank his teeth in just above the collar. Peter sucked hard, and Tony sounded surprised as he said, "Oh, that's—that's good."
Peter licked the mark he'd left, then pulled back to admire it. He wanted to make more. "You said something about toys?"
"A whole trunk full," Tony confirmed.
He retrieved it from the closet, muscles shifting as he lifted it, and Peter took the opportunity to adjust himself. They hadn't even taken their clothes off yet, but Peter was as affected as if they'd spent the last ten minutes rolling around naked in bed. Then Tony popped the trunk open, and—
It was a lot. Peter didn't know what half the things in it were. Most of the ones he recognized, though, he really, really wanted to use. He wanted to use some of the ones he didn't recognize. There were floggers, a cane, and a cat o' nine tails. There was a feather teaser stored next to something pointy and round. There were alcohol wipes and a straight razor, maybe the only thing Peter wasn't interested in. There were ropes and handcuffs and a silk blindfold. There were just—a lot of things to try. Peter was spoiled for choice.
Tony stepped back. "What do you think?"
Peter looked at Tony. "I think you should take off your shirt." Tony did, dropping it on the floor beside him, and Peter discovered he liked having Tony do what he said, too. "Now your socks." Peter swallowed as Tony bent down and pulled them off one at a time. "Belt next." Tony made quick work of it. When he went to put it down by the shirt, and Peter said, "Wait. Give it to me." He held out a hand, and Tony didn't hesitate to pass it over. Tony put his hands to the button of his slacks, but paused. He waited for Peter to give the order, and Peter felt a swell of something possessive and deeply affectionate as he said, "Go ahead. Take off the rest."
Tony popped the button with shaking hands and drew the zipper down slowly. His hips did a little shimmy as he pulled down both underwear and slacks at once. He stepped out of them, toward Peter, clad only in that brown leather collar.
Tony's voice was quiet, hushed, as he asked, "What next?"
"Turn around." Peter didn't recognize the confidence, the command, in his own voice, but the hunger—he felt that the whole way through. Part of him didn't believe this could be real as Tony obeyed him.
"So are you going to tie me up or hit me with it?" Tony asked. "Or is it going to be a surprise?"
"Do you have a preference?" Peter asked, running his fingers along the stitching of the belt's edge.
"Only that you disinfect it first if you use the belt buckle. Wipes are in the trunk."
Peter stepped up behind Tony, and Tony tensed, but didn't turn around. Peter traced Tony's spine with his fingertips, then with the leather. Tony relaxed, moment by moment, inch by inch. Peter dropped a kiss on his shoulder, and Tony shivered.
"Fan of suspense, huh?"
"Maybe I haven't decided what I want yet." Peter pressed another kiss to the back of Tony's neck.
"Take your time. Or not. This is your show, here."
Peter made his decision. "Put your hands behind your back."
Tony clasped them, and Peter wrapped the belt around his wrists. Tony flexed his arms, then shook his head. "Too tight." Peter tried again. Amusement leaked into Tony's voice as he said, "I'll grant you that that's looser, but it's going to fall off. One more time, Goldilocks."
"Maybe I should have just hit you with it," Peter said as he made an attempt at a happy middle.
"Still could," Tony said cheerfully.
Tony flexed again. He hummed. "Just right."
Peter took a step back. "Get on the bed?"
"Are you asking me or telling me?" Tony said.
Peter gave him a nudge. "Telling you."
"On my stomach okay?" Tony was already crawling onto the mattress, awkward and unbalanced with his arms bound behind him.
"Sure," Peter said. It kept hitting him, over and over again, that he had no idea what he was doing. He walked to the trunk, picking toys up and setting them back down. He had the feeling Tony was right about him preferring to use his hands. "Is there—do you have any rings?"
Tony turned his head and struggled partly upright again. "Not in there. Check the closet. There's a small jewelry case." He tipped his chin that way. "Ooo, grab my class ring."
Peter found it. Tony's MIT ring was a bit big on Peter, loose on his index finger, but it fit his middle finger. He returned to the bedroom to find Tony had gotten back on his stomach, waiting with a surprising amount of patience. Peter sat on the mattress next to him, running his hands over Tony's back and sides.
"If you want to get my face, I'm going to have to sit up or roll over," Tony said. "Whichever you'd like. I'll even beg, if you want."
"And then you get a treat?"
"Oh, trust me, I'm already getting a treat." Tony shivered as Peter traced his fingers along the curve of Tony's ass.
"I kind of like you where you are." Peter dug his fingers in and spread Tony's cheeks.
"Got me right where you want me?"
Peter watched, fascinated, as Tony's asshole twitched and fluttered. He wasn't even doing anything. "I think so."
Tony groaned. "I really am close to begging here."
"What do you want?" Peter asked, letting Tony go. There were white marks in the shape of Peter's fingers.
"Anything. Whatever you want to do, do it." Tony rubbed his jaw against the sheets. "Just, please, do it soon."
Peter made sure the ring was facing out. He petted Tony's ass a couple times, then lifted his hand up, gave Tony a moment to anticipate it, and brought his palm down with a sharp slap. Tony's whole body jumped beneath him. Like with Tony's face, Peter evened him out here, too.
"How's that?" Peter asked.
"I think I'm going to break my dick on this mattress," Tony said. He spread his legs. "At the very least, I'm going to need to change the sheets."
Peter felt warm all over. He turned the ring inward and petted Tony's ass again, letting him feel the face of the ring, the stone and the ring's edge, the lettering around it. Peter swallowed. "Okay?"
"Definitely okay." Tony nodded. "Very, very okay."
When Peter's hand came down this time, Tony yelped.
Peter snatched his hand back. "Are you okay? I'm so sorry, I thought, I shouldn't have—"
Tony burst into laughter. "Sorry, sorry, I just—it's okay. I'm fine." Peter could see the curve of his smile. "I'm good."
"Are you sure?" Peter hesitantly put his hand back on Tony's ass, stroking where he'd struck.
"I promise, even if I scream, unless it's the word no, stop, or something along those lines, it's not a bad sound." Tony's shoulders were shaking with his mirth. "You're doing great."
Peter did not feel like he was doing great. Peter felt like he was out of his depth. He undid the belt on Tony's wrists, admiring the red lines and indents where Tony had pulled at it. Peter leaned down and traced them with his lips, his tongue.
"Are we going with honor bondage now, or are we done?" Tony asked. He didn't try to move his arms.
"We're not done, but I think I'm done tying you up tonight." Peter kissed Tony's elbow, then sat back. "You can move your arms, but don't roll over yet."
Tony pulled his arms forward, pillowed them under his chin. "Going to spank me again? If you put me over your knee, you'll be able to feel how much I'm enjoying it."
"Tempting," Peter said. He drummed his fingers against Tony's hip. "I can do anything?"
"You already know my limits. Go for it, kid."
"Is there a time limit?" Peter asked.
"That's an open-ended offer," Tony said.
"No, I mean, is there anywhere you need to be tonight? Anything you need to do?"
"I'm all yours."
Peter closed his eyes. When he'd gathered himself, he said, "Okay. Let's, um, let's try the knee thing."
They repositioned, Tony sprawled across Peter's lap. Tony's ass was in the air, his erection pressed shamelessly into Peter's thigh. Peter took a minute to fondle him, alternately stroking Tony's skin and digging his fingers into the muscle.
"You're sure you don't have anywhere to be tonight?" Peter asked.
"Just right here," Tony said. "It's a very good place to be."
Peter turned the ring facing outward again. At the first slap, he felt Tony's dick jump against his thigh. At the third, Tony made a tiny involuntary noise. By the twelfth, Tony was grinding into Peter, hips moving helplessly between every hit. Peter's palm was going numb. Tony's ass was bright red.
"Can you come like this?" Peter asked.
"Fuck," Tony said. He was trembling. "I don't know? Maybe. I don't—" Peter's hand came down, and Tony gave a breathless, "Ah!" He said, "Keep going, and we'll find out."
Peter kept going. Tony had started vocalizing with every slap of palm against cheek, formless sounds devoid of meaning. Whenever Peter paused to pet at the abused flesh, Tony whimpered, squirming and seemingly unable to keep still.
"I cannot believe," Tony panted, "I never realized how much I would be into this."
Peter froze. "What?" Tony didn't answer him, rocking into Peter's thigh, and Peter said, "Tony, what does that mean?"
"Can we please talk about this later?" Tony said.
"No," Peter said.
Tony groaned. He pushed himself up. His eyes were dark, the brown of the iris a thin rim around blown pupils. His face was flushed, sweat starting to bead at his temples. His smile was slightly rueful.
"Tony, that—you just—" Peter blew out a breath. "That sounded a lot like this isn't something you've done before."
"Yeah." Tony drew the word out. "About that."
"You have—there are all those toys!" Peter pointed at them.
"And you—those are yours, right?"
"They're mine." Tony winced a little as he settled himself cross-legged on the bed. "They are definitely mine."
Peter was feeling a little bit hysterical right now. He couldn't quite get out a full sentence. "But you've never—?"
"Not from this side of it," Tony admitted. "At least, not more than once or twice a very long time ago."
"You said you were flexible!" Peter waved a hand.
Tony captured it in his own. "And for you, I am. More, maybe, than I realized." Tony twined their fingers together. "I didn't lie." He gestured at his own lap with his free hand. "I really am having a good time. A very, very good time. Any better, and I wouldn't be hard anymore, because I'd have already come."
Peter reached out and tapped the collar with his left hand. "Do you even like wearing that?"
"I like the way you look at me when I'm wearing it," Tony said frankly. "Like I'm something you covet, like I'm someone you plan to keep. I don't mind a few extra trappings to get you there."
Peter tried to pour every bit of earnestness he felt into his expression when he said, "You don't need a collar for that." He touched Tony's cheek. "I've been there this whole time. You just weren't paying attention."
Tony turned his head and kissed Peter's fingers. "I'm always paying attention to you."
"If that were true, I don't think it would have taken you getting kidnapped to figure out that I wanted to date you."
"I'm maybe not so great at reading what I'm seeing," Tony admitted.
"Then let me be as clear as I can: I don't care if you're wearing a collar. I want to keep you." Peter squeezed Tony's hand. "You look good in it, but you look good in everything."
Tony's gaze was intent. "You mean that."
"Of course I mean it." Peter leaned forward, knocking their foreheads together. "I already told you that it's always you."
Tony cleared his throat. "It's—it's always you for me, too." He gave Peter a lingering kiss. When he pulled back, he suddenly smiled. "But again: I really did like what we were doing." He ran his thumb over the tendon of Peter's wrist. "I wouldn't be opposed to going back to that."
"You're not going to be able to sit tomorrow," Peter said.
"But how could you live with yourself if you didn't find out tonight if I can come from spanking alone?"
"You were getting plenty of stimulation from my thigh." Tony pouted, and Peter couldn't hide his smile. "That's not a no."
"Yes." Tony finally released Peter's hand to flop over into his lap. He made a gesture, finger twirling in the air. "As you were."
Peter laughed. He picked up where he'd left off.
Turned out that yes, Tony could come being spanked, so long as he could rub off on Peter's thigh at the same time.
Peter hadn't ever really thought about it, the things he could do to Tony—the things Tony would let him do. The things Tony might want him to do.
"Think it over," Tony said. "I'm sure we'll find more things we both enjoy. If nothing else, it'll be fun figuring it out."
Peter hadn't ever really thought about it, but he was about to make up for lost time.
Tony was right there with him.