#insertion

In the dark, blue-cast dimness of Steve Rogers’ bedroom, Scott Lang hums the Mission Impossible theme song to himself as he parkours over the peaks and valleys of Steve’s rumpled blanket. Each ridge of fabric is its own hill, its own towering cliff, made for Scott to dive over and plummet into soft, bouncy mattress with a whispered, hi-ya!. It’s a stealth mission, and despite how much noise he’s making by muttering to himself, he’s confident he won’t be discovered. He’s far, far too small for that. No whispered words will carry across the miles and miles of bed to Steve’s sleeping ears, of that he’s confident.

He has one single destination in mind, and when he finally makes it up the steep slope of Steve’s muscular thigh to stare between his legs, he cannot help but raise a hand to his forehead in a reverent salute. God Bless America, Steve Rogers sleeps naked. His private stands at half-attention, and thank god, that only makes Scott’s job about a million times easier. You see, he has exactly one goal for tonight’s mission.

Tonight, Scott Lang is going to visit Captain America’s balls. It’s been in his head for so long, he’s lost track. It all started with a particularly saucy dream he had, some indeterminate number of months ago, and ever since then the thought keeps circling back into his mind like an obsession. He can’t quit it. It won’t leave him. The concept of shrinking himself down small enough to squirm his way down that titanic shaft, of dropping all the way into his perfect, soft sack, of being at the very source of things, has invaded nearly every waking moment.

So, he’s just going to do it once. Just this one time, just for a night, just to get it out of his system – and then, once the itch is scratched, he’ll sneak his way out again and leave Steve none the wiser. Nobody gets hurt. He never even has to know. It’s a victimless, sexy, sexy crime, and Scott is nothing if not super good at being a criminal. A smooth criminal. They should turn that into a song, or something.

Anyway, never mind that – mission focus. The very first objective here is obvious: he’s got to scale Steve’s half-hard cock. It shouldn’t be too difficult; it’s just soft enough to be sloping upward toward his belly still, curved and easily conquered by the weight of the blanket. If he can get to the base, he can scale along the underside of his shaft, walk along the curve, hop up onto the head, and then start working himself down into Steve’s slit. Easy, right? Right. Piece of cake.

Except, the trouble arises once Scott is about halfway up the glorious, lightly veiny underside of Steve’s magnificent cock. He didn’t factor into his calculations just how sensitive Steve’s serum-enhanced nerve endings are. Although he’s barely a quarter of an inch tall, the weight of him still feels like the light, barely-there touch of a fingertip dragging its way softly along Steve’s length. That’s more than enough stimulation to send Steve’s dreams veering into extremely pleasant territory, more than enough to send a rush of warm, interested blood pulsing into his dick. It begins to rise – slowly at first, but then with emphasis, pressing back against the weight of the blanket and stiffening swiftly.

“Woah, big guy!” Scott calls, scrambling to grab ahold of loose, velvety skin to keep himself from sliding down what’s rapidly becoming a ninety degree angle on this wall of flesh he’s scaling. He flattens his body against it and grips on tight as it levels out, towering over him, suddenly standing on business.

It’s a little more precarious from there, but Scott manages. At long last, he finds himself standing on the tip of Steve’s cock, staring down into the dark, gaping, moist tunnel beneath him. The thought of what he’s about to do has him twitching in his suit, but there’s no time for that right now. There’ll be plenty later, once he’s safe and secure, snug as a bug in a rug inside one of those beautiful balls.

He takes a deep, steadying breath. Here goes nothing. And he dives in, sliding down steeply angled precum-lubricated flesh like a slip n’ slide. As he goes, his tiny body drags along the hyper-sensitive nerve endings on the inside of Steve’s cock, and electric-hot pleasure courses through him so strongly, he stirs awake with a muted little gasp. Around Scott, the tunnel gradually narrows, pulsing almost closed with the strength of a needy throb.

From deep below, a geyser of precum begins to build and push up, threatening to take Scott with it. He yelps, flailing, doing his best to push himself through the thick liquid, swimming against the current, fighting his way downward. So close… can’t… slip…

Things become chaotic when, outside, Steve idly reaches down between his legs and grasps his cock, stroking out a soothing rhythm in a manner that feels lazy and slow for him, but that jiggles and shakes the entirety of his package for Scott. He can just see the narrow passage, his ultimate goal, so near the finish line he can taste it.

With one final push of maximum effort, Scott goes tumbling, dropping down into a waist-high pool of hot magma cum. The room he’s in is sloshing, rising and falling in waves like a ship at sea in time with Steve’s strokes. Scott can see the hot pink walls of flesh all around him, the steady collection off cum building up on the walls, rising gradually higher as Steve fills his balls with the accumulating force of his arousal.

It’s absolutely everything he hoped it would be. He reaches out in awe, stroking a wide palm along the sensitive inner wall, and he’s surprised to feel the entire room respond around him, pulling taut and tightening up as a long, low groan reverberates down from above. Holy crap is that hot – knowing he can stimulate Steve from the inside like this, knowing he can inspire all kinds of sensation despite being so small, just due to the nature of where he’s camped out in Steve’s privates…

He can’t help himself anymore. He throws himself down like he’s dropping into a hot tub; the liquid swishes around his throat, high enough to cover almost all of him, but not quite high enough that he can’t see. Perfect for him to relax back against the bouncing, rounded flesh behind him and take himself in hand over the fitted confines of his suit.

Outside in the real world, Steve has absolutely no idea what’s sparking this constant roll of heat, but sensation after sensation sparks through him, shocking and liquid in its desire. It pools low in his belly, it sings through his balls, it feels incredible.

Together, in a manner only Scott knows to find companionable, the two of them build a quickening rhythm. Steve’s balls bounce; Scott learns to ride the wave, and he allows the momentum of it to set his own pace, matching beat for beat. The liquid around him rises, sloshing up over his head at times, coating the mask over his face. That, too, is hot – if he’d take a facial from anybody, it would sure as hell be Steve God Bless America Rogers.

They reach crescendo at the same time. Scott’s world is thrown into turmoil as Steve begins to spill, the liquid all around him surging and rushing for the exit, the room seizing up, balls bouncing wildly, all sense of structure abandoned for wanton lust. He contributes a meager droplet to the tidal wave of it all and, after what feels like endless ticking seconds of surging-hot climax, he finally collapses back against Steve’s mostly-drained balls again, breathless, panting.

And that’s just the first round. You bet your ass he’s getting his money’s worth. He’s got to hand it to the guy, he’s deeply impressed with Steve’s recovery time. Barely any readjusting himself inside of Steve’s balls gets the liquid flowing again, gets him stirring again, gets him horny again. Within only minutes, the slow rhythm starts up as Steve begins his second round of masturbation, and Scott has to spend a little while catching his breath before he can keep up.

By the time the sun is properly up, by the time Scott has gotten his fill, hours have passed and Steve has gotten off no less than five separate times. Scott, try as he might, managed only a respectable three before finally giving out after the last one, collapsing in an exhausted heap, fondly daydreaming about Gatorade and orange slices.

“Alright, pal,” he pants, absently patting Steve’s inner walls like one might pat a particularly good horse. “I think that’s it for me. This has been great. Really. I mean it. Ten out of ten from the judges.”

Gingerly, so as to not inspire too much more sensation in Steve’s sack, Scott stands. The exit overhead is just a little bit too high for him to reach, and the walls are too slippery-slick and rounded for him to climb. It’s no problem, the solution is simple – all he has to do is expand himself a little bit until he’s just tall enough to reach, grab on, and then shrink again to crawl his way out. No problemo.

This is how Scott learns that super-soldier serum laced precum has a very, very strange reaction to Pym particles. Tweaking his size seems to sort of work, in that he grows a flickering, fleeting couple of inches from his own perspective, but not nearly the amount he’d been angling for. No, no… the answer becomes clear when, distantly, he can hear the sound of a bedframe cracking in two, and Steve’s voice all around him crying, “What the hell-”

Steve Rogers has stolen about ninety-five percent of the growth Scott intended for himself. Several feet and a couple hundred pounds of muscle later, a bewildered Steve Rogers crowds his claustrophobic bedroom, confused – and deeply, deeply aroused.