A/N: Warning for tentacle porn.

Steve stares at him in shock. His mouth opens twice before snapping shut again and each time it does nasty things to Tony's heart. What if Steve is disgusted? He's always been more than accepting of the numerous and varied mutations they've encountered but what if it's different now that it's someone Steve considered a friend? What if he's mad at Tony for keeping this a secret from him, Tony's best friend and leader of the Avengers? Not that Tony will apologize for it. He'll stand by his decision to keep it secret, so if Steve is about to berate him for not bring it up sooner he'll-

"Are they… mechanized? Do they-" Steve sighs and rubs his forehead with the heel of his hand.

Tony can see the cogs trying to turn, gummed up by the new information. Steve meets his eyes and he looks lost, adrift at sea with nothing to help him stay afloat.

"Tony, is this... is this one of those fetish things?" Steve has a pinched look about his face as he asks the question and Tony has to stop himself from laughing. Both at how adorably confused Steve is and the flood of relief that maybe Steve will be okay with everything.

"Well, if you've spent any time on the seedier places of the internet you'd know it is for some people. But for me? No. These are one-hundred percent real. Had 'em my whole life. Obviously I don't have them all the time but every few-" He stops when he notices the look on Steve's face, they way his eyes are roaming the tentacle that's resting near Tony's elbow.

"Steve," Tony says, low and careful. "Is it 'one of those fetish things' for you?"

Steve is taken aback, and his eyes snap back up to Tony's, a light flush marking his cheeks. "No-no. That's not something I've ever thought about-"

Tony grins. "You're thinking about it now, though. Aren't you?"

The light pink on Steve's cheeks grows more pronounced and spreads down his neck. He clears his throat before speaking. "Well we, ah, we haven't even kissed yet."

This time it's Tony who's thrown for a loop. He was talking in generalities, making fun of Steve's obvious discomfort and confusion. The most he was hoping for was to prove to Steve he's still the same Tony he's always been, to make sure Steve is okay with everything and to not lose Steve as a friend. Tony's not at all prepared for the idea that Steve is both okay with the tentacles and apparently also wouldn't mind kissing him. Not to mention the fact that Steve hadn't said no to the tentacle thing.

Tony's never told anyone about this, he never imagined anyone could possibly want him in this form. The very idea sends an electric shock down his spine. He never thought he could fall more in love with Steve Rogers but this moment has proved him wrong.

He lets one of his tentacles slide out of the tub and curl around Steve's ankle. Steve doesn't move, just glances down before meeting Tony's gaze again.

"How about you hop in and we can take care of that?" Tony asks.

Steve's fingers twitch where they hang next to his hip and he looks like he's torn between taking a step back or stripping off his clothes and jumping in. Instead he stays put.

"Are you… do you have to stay in there?"

"Short answer: yes. Long answer: I'll probably be in here for at least eight hours if not longer. I went too long without-well, I can explain the details to you later once you've had a little time to let everything soak in."

Steve nods a little loosely, still looking a bit dazed.

"You getting in? The water is perfect… and if it's too cool for you I'm sure we can figure out a way to warm you up."

Steve's eyes come into abrupt focus and he takes a half-step forward before shaking his head and taking a step back. Tony releases the grip on his ankle a little reluctantly, stomach dropping. But before Tony has time to work himself up into a state of self-hate, Steve bends down and slips off a boot. And then the other.

Once it hits Tony that Steve is actually going to join him, he moves back a bit and enjoys the show as Steve slowly strips out of his uniform. When he's down to just his pants he hesitates a moment, thumbs hooked in the waistband, and then shucks them as well. It looks like the blue briefs are staying on, though, and Tony allows himself a moment to lament the obstructed view. Only a moment, though. There are plenty of other things to look at-and hopefully touch.

Steve walks hesitantly to the edge of the tub and then sits down in a fluid motion, letting his legs hang into the water. Tony isn't sure if he should back away and let Steve come to him or if he should move closer and remind Steve of why he's there. Always an instigator, Tony moves forward; Steve's eyes flick up to his and then down to the swirl of tentacles below the water. As Tony approaches, Steve's legs drift apart of their own accord and Tony settles between his knees.

Bright blue eyes meet his as Tony lets his hand rest on Steve's knee. A bashful smile overtakes Steve's lips and the strangeness of the situation has Tony grinning at him in return. Steve lays one of his own hands on top of Tony's and leans forward, his free hand coming up to cup Tony's face. Tony leans into the touch, closing his eyes for a moment.

A soft pair of lips press against his own and he squeezes Steve's hand in encouragement, Tony letting Steve lead this one. It's soft and tentative. It's earnest and pure in the same way that Steve's personality can be. But Tony knows Steve, he knows Steve's layers, and somewhere under that wholesome coating is a man who's ready to get as dirty as the rest of them if it's for the right reasons.

Kissing Steve is better than anything Tony could have hoped for.

Kissing Tony is perfect. Sure, Steve hadn't expected it to happen today, and he definitely hadn't expected it to happen right on the tail of finding out his best friend for the past few years is actually some kind of part-time octopus merman… thing, but the kiss itself is perfect.

He knows that Tony is letting him lead the show, letting Steve set the pace, and all that knowledge does is make Steve want Tony more. The idea settles and curls in his abdomen, fire licking up his spine as he swipes Tony's lips with his tongue.

Tony shifts forward, mouth opening, pressing his body tight against Steve's and letting go of his hand, moving it to his side. It's an awkward angle, with Steve still sitting on the edge of the tub, giving him at least a foot over Tony. A tentacle slides idly around his ankles; Steve pulls back from the kiss and gasps as they give a sharp yank and he's pulled forward the rest of the way into the tub.

It's deep, the water coming up to just under Steve's shoulders. It's warm, too, but Tony's body is warmer still and Steve's arms circle Tony's waist and pull him back into the kiss. This time Steve lets himself give in to what his body really wants to do. He kisses Tony passionately, their slick tongues caressing and teeth nipping, eliciting small noises from each other. He moves his hands to the back of Tony's neck, tilting his head for a deeper kiss, fingers delving into the short hair that's grown out just enough to start curling on the ends.

That's when Steve feels the first one slide up his leg. His breath hitches in his throat at the surprise but otherwise he does nothing but continue ravishing Tony's mouth. Taking Steve's lack of running away as permission, the water moves around Steve as the other tentacles move in to caress him.

Before long, they're everywhere. Tony is everywhere. His tentacles are sliding over Steve's skin, mapping out his body, caressing and rubbing. He's not sure if there's a patch of bare skin left on him that hasn't been explored and oh god they're going to drive him crazy. It's overwhelming, his skin more sensitive than the average human's thanks to the serum, and Tony's tentacles are so soft and so careful that Steve's mind is already lost in a haze of lust.

This was only supposed to be a kiss, their first kiss, Steve thinks. But he should have known better. With the long-simmering crush he's had on Tony for the past few years there's no way this was ever going to be something as simple and chaste as that.

He feels one wrap high around his thigh, but this time it's not the soft and smooth side. He gasps and his hips jerk involuntarily.

"Oh, god… they're suction-y. That feels so strange." He manages to say around the kiss.

Tony pulls back, looking concerned; Steve feels the tentacles moving away, and Steve absolutely refuses to let that happen.

"I didn't say stop," he says, before he pulls Tony back in, biting at his bottom lip. Steve presses his hips forward, letting Tony know just how much he's enjoying this.

Tony laughs into the kiss and nips at Steve's lips in return, and at once his tentacles are roaming all over Steve's body. One slides and squirms its way up Steve's chest, between his body and Tony's. He leans back and looks down as it traces the lines in his muscles, his abs twitching at the feeling.

"Can I- can I touch it?" Steve asks softly.

Tony grins at him. "You are allowed to touch anything and everything. Carte blanche."

Steve feels his cheeks heat at the implication but lifts his hand from Tony's side and softly carresses the back of the tentacle between them.

Tony inhales sharply and Steve jerks his hand back.

"No," Tony says.

Steve looks at him, his pupils are blown and lips parted.

"Sorry, keep going. I've just never-no one's ever-" Tony flounders for words.

"No one's ever touched you like this?" Steve asks.

Tony shakes his head. "My mother used to sit with me when I was a kid but it didn't feel… like that. And no one has seen me like this since."

Steve's not quite sure what to do with that information. He's still little upset that Tony felt the need to hide this from everyone, from him. He won't lie and say that's it's not a little strange but it's strange in the unique, crazy, amazing way that Tony often is. It's actually rather… fitting. But the fact that no one else has been here, like this, causes a shameful burst of desire to flow through him.

Steve sets his hand back on the tentacle and runs his fingers lightly down its length. Tony exhales again, slowly, and his tentacle moves up, pressing gently against the side of Steve's face, cupping his cheek. Steve caresses down where it's thicker and turns his head, pressing a kiss to the underside. The skin is soft and slick, and Steve's never felt anything quite like it before. The tip of it is thin in comparison to the thickness of the rest of it, and Steve moves his head back further, catching it with his lips. He kisses it lightly, then opens his mouth and takes it in an inch, swirling his tongue around, and watches as Tony's face darkens with desire.

"Oh god, Steve."

Steve takes the tentacle a little deeper into his mouth, his tongue in constant motion, his hand fingering lightly around the suckers. He feels Tony's hands tighten on his waist and sees the way his breathing has turned shallow and erratic. Another tentacle brushes by his free hand and Steve strokes it slowly, his own desire being fed by the sight of Tony.

Tony pulls the tentacle out of Steve's mouth slowly, watching as it drags across Steve's lips, and then wraps it around Steve's wrist. It's tight but not painful and Tony pulls Steve's hand down. Steve, curious, tries to resist for a moment and is floored by just how strong Tony is. He instinctively knows that Tony would be able to hold him down like this, he'd be able to wrap tentacles around each of Steve's limbs and stop him from moving, he'd be entirely at Tony's mercy.

The tentacle Steve was stroking jerks out of his hand and wraps around his forearm, and then moves Steve's hand down. Both his arms pressed to his sides by the tentacles, Steve attempts to move them and is rewarded with a surge of lust when he finds himself unable to do so.

Tony looks at him for a moment, licking his lips. "So, over the years I've done a few experiments when I'm like this. Just learning my limits and finding out if it's just the tentacles or if there are any other changes that I'm not noticing."

Steve gives him a curious look.

"There's one thing I've found out that's really interesting," he says, and Steve can feel tentacles curling around his ankles as he speaks.

"I found out that my lung capacity increases exponentially," He leans forward and brushes his lips against Steve's ear. "Guess how long I can hold my breath?"

Tony's voice is husky and low and it shoots straight to Steve's cock; he lets out a small moan and hears the huff of air that is Tony's laughter ghost by his ear.

"My record so far is fourteen minutes and eight seconds. Should we see if I can beat that?"

Steve exhales as Tony leans back to look him in the eye. He doesn't tell Tony that Steve doesn't think he'll last even close to that long. He doesn't tell Tony anything, afraid of what his voice might sound like, already sure that his pure desire, his palpable want must be clear on his face. Instead he just jerks his head up and down. Tony smiles a dirty smile in return.

The tentacles don't let go of Steve's limbs, but Tony kisses him quick and dirty before he's sliding down Steve's front. Steve can hear him inhale as his head goes under the water completely and Steve watches as Tony hooks his fingers in his underwear and carefully slides them down. The tentacles release Steve's ankles, allowing Tony to remove the clothing completely, and then Steve feels them twining around his thighs and he spreads his legs without thought.

Tony's hands run along Steve's hips, rubbing the indentations created by his muscles. Everything feels so good, every touch and every movement but nothing prepares him for being wrapped in the warm heart of Tony's mouth. It's so much warmer than the water around them and Steve bites back a groan as Tony swirls his tongue around the head of Steve's cock.

Tony's head bobs under the water slowly, torturously. Every drag of lips and every movement Tony's tongue makes is pure bliss, sending waves of heat through his body. A tentacle works its way around Steve's waist and to his back, almost as if providing support. Another one joins in by coming up and slowly rubbing at his chest, circling his nipples, dipping into his belly button… touching every part of Steve it can.

Steve's skin is ablaze with sensation and the warmth is curling hot in Steve's belly as Tony continues to move. Every stroke is a new inferno, every movement of tongue is rocking Steve to his very core. He lets himself get lost in the haze of feeling and lust. His mind is alight with pleasure.

He feels a tentacle caress the skin where his thigh meets rear and his breath catches in his throat. It slides up carefully, slowly, tracing his crease and then pushing a little harder until it's rubbing a gentle circle around his hole. Steve's hips buck slightly but the grip Tony's tentacles have on him is firm and he barely moves an inch.

The tentacle circles his hole carefully as Tony picks up speed, the movement of his head causing the water to lap around Steve's shoulders a little more harshly. As Tony tongues his slit, the tentacle presses in and the air leaves Steve's chest. The tip is thinner than the rest, of course, but it's still an unusual feeling for Steve; overwhelming. The tentacle presses in further and then stops, waiting for Steve to get used to the feeling, while Tony's mouth on Steve's cock never slows.

Steve can feel himself relaxing and slowly the tentacle starts to move. It thrusts lightly in and out, the tip curling, Tony's head moving faster. He lets go of Steve's hips and uses his hand to help with what he's unable to fit in his mouth and, god, Tony must have been underwater for ten minutes now and he's showing no signs of letting up.

The tentacle inside him shifts and sparks light up behind Steve's now-closed eyes; Tony must know that he's hit Steve's spot because he attacks it relentlessly. The tentacle thrusts in and out and with every drag it rubs across the spot that's making Steve go dizzy. Tony works his mouth in counterpoint to the thrusts and Steve is thankful for the tentacle wrapped around his waist because he's not entirely sure he'd be able to hold his own weight like this.

He can feel his impending release, he's so close. His body is strung taut, hips twitching and jerking as much as they're allowed and he's pretty sure he hasn't stopped moaning since the tentacle entered him. A handful more thrusts and the quick motion of Tony's tongue and he's coming harder than he ever has before.

"Fuck," he moans as Tony works him through the orgasm, insistent on wringing him completely dry.

It's a moment or two before the tentacle slows and slides out of him, leaving Steve feeling strangely bereft. The tentacles around his arms and legs loosen as Tony rises, but the one around his waist, the one holding him up, remains in place, much to Steve's gratitude.

Tony breaks the surface with a dirty grin on his face, pushing his wet hair back with a hand. He glances up in the corner of the room and his smile turns speculative.

"Huh. A little under thirteen minutes. Guess we'll have to try to break that record some other time."

Steve lets out a growl and uses his now-free hand to pull Tony's head in for a kiss, the taste of himself on Tony's tongue just another thing to fantasize about later.

When they break apart, Tony is still smiling and Steve can't help but to grin back and rest his forehead on Tony's, breathing hard. He wraps his arms around Tony; Steve may be spent, but he still can't seem to get enough of Tony.

"God, Tony. That was-"

"Amazing? Spectacular? The best orgasm of your life?"

Steve rolls his eyes but laughs all the same. "All of the above, I suppose," he says. He pulls back when a thought occurs to him.

"Do you-can you- in this form, I mean."

Tony shrugs. "It's not something I've ever really tried. It's kind of hard to be in the mood like this when most of the time I'm in here alone just counting down the hours until I can get back to work. Plus there's the fact that, uh, I'm missing some equipment when I'm in here."

Steve's eyebrows go up.

"Yeah, yeah, yeah. Don't say a word. I'm still the epitome of manly even without one, alright?"

Steve laughs. "I wasn't going to say anything! I just didn't realize..."

"Although," Tony starts and trails off.

"Hmm?"

"It actually felt really good when you used your mouth… That's definitely something I've never felt before. I'm not saying I could come from it but… there were stirrings."

Steve smiles and glances over his shoulder at the clock, then looks back at Tony.

"How much longer until you're done in here?"

"I can probably shift back in a little over seven hours, but with you here I might not be done for quite some time."

Steve feels his cock twitch but super soldier or no, he's still going to need a few minutes before he's ready to go again.

"Mmm. Well, since we have some time yet, we should probably explore that. For science."

Tony's responding grin makes Steve's heart do a funny thing in his chest.

"I don't think you're realize what you're in for here, Rogers. But I'm all about letting people make their own mistakes. Show me what you've got."

Steve knows they'll have to talk about this later. There are conversations they'll need to have regarding what this means to each of them, what they are looking for here. They'll have to discuss the details of Tony's situation and make a few plans... there is a lot of talking to be done.

But with the tub and Tony in front of him and at least seven hours to go… there'll be plenty of time to talk later. For now, Steve is on a mission.