Sam only discovers that his brother wears diapers because he finds one in the trash can in the bathroom. He’s discarding an old tooth-brush, and there’s a neatly wrapped up bundle at the bottom. He investigates, suspecting Dean to be keeping a serious injury hidden, and he wants the bloody bandages for proof to make Dean give in and let him look at it. But it turns out that all the bundle contains is a diaper. And his first thought is ’GROSS!’, and cursing motels where apparently the maid doesn’t even empty the bathroom trash can. But curiosity wakes as he realizes that the material is in fact an adult diaper, and not dirty, even though it’s crinkled like it’s been worn for some time. He carefully sniffs it, to confirm that it hasn’t been used. That bit of info drowns, though, as he’s hit by an intense olfactory portrait of his brother.
He drops the diaper as if he’s been burned, and stuffs it back into the trash can as quickly as he squashes down the images in his head of Dean in a diaper. He even manages to finish his morning shower, including a down-to-business, rough wank, without thinking the least bit about it.
But in the days to come, somehow his attention wanders to little details.
He starts noticing when, and how often, his brother goes to the bathroom. He finds himself evaluating Dean’s choices of clothes from a different perspective. The 501’s don’t look too tight, but they sag a bit over his brother’s ass to start with. And modern, adult diapers are thin. The long, roomy shirts just about covers him up anyway. It doesn’t seem like Dean doesn’t use the bathroom in an ordinary way, though. Which is confusing, because why else wear diapers, except to escape the rather disturbing public restrooms that are part of their life. Sam admits to himself that he might actually understand that.
Now that he knows what to look for, he finds more diapers. But still, none of them are dirty. Which seems somehow sad. Until the moment when he finds one with semen stains inside it. He stares at them for a few minutes while he tries to lie to himself again. But he’s too far into it now – knowing that his brother apparently wears diapers to get off in them, he can’t pretend to not want more of this, be part of this, watch Dean wear them and actually use them… He shudders and realizes he could almost come in his pants.
He can’t tell Dean that he knows. But he starts figuring out ways to bring him to use the diapers for more substantial secretions than ejaculate. He starts plying him with coffee. Really strong coffee. But, Dean’s system seems to be used to it, and anyway, even if he has to go a bit more often than usual, he still manages to find rest rooms or trees by the road-side when needed. It’s sort of difficult to refuse to stop, with no-one chasing them, and Dean behind the wheel most of the time. But even just watching Dean getting restless and preoccupied gets Sam excited now. It’s almost unbearable, not to see it through.
Then his chance turns up. In the morning, they’ll need to cross Nevada, and since Dean has gotten pretty hammered tonight, it probably won’t be a problem to claim the driver’s seat tomorrow. As Dean snores on the other bed, he gets up and fetches the bottle of little, orange pills he’s been keeping hidden for a while, now. He doesn’t want to give diuretics to a guy who’s already hung-over, but he’ll probably need to pee all on his own, so Sam has decided on laxatives, only, counting out a dose that’s neither excessive, nor negligible.
Next morning, Dean is just as grumpy and unattentive as Sam expected, and he has no problems sneaking the powdered pills onto his brother’s break-fast plate, while Dean downs several cups of coffee. The excitement is almost impossible not to show, but Sam forces himself not to fidget, or stare too obviously at Dean. He sees to it that they pack up in a hurry, and then they set out across the desert.
For a few hours, Dean sleeps like the dead in the passenger seat, leaned against the window and wrapped up in his jacket. Sam tries to imagine what’s happening inside him. All the fluid and waste in his body must be starting to pool in his bladder and rectum. Sam watches him out of the corner of his eye, and yeah, his brow is starting to crease, and he’s shifting in his seat. Sam hears gurgling noises from his body, and sees him wrap his arms more tightly around himself. His eyes slit open, and he raises a hand to rub at his face, grimacing.
’Whoa, I don’t think I should have had that last cup of coffee. Any rest-rooms in sight?’
Sam stares ahead at the road, running straight into the horizon.
’Not really. Do you want me to stop here?’
He’s taking a chance, but he’s pretty sure Dean’s stomach is bothering him more than his bladder, and he knows Dean won’t squat down by an empty road-side, wearing a diaper, unless he’s really desperate. Hopefully, desperation will rather convince him to use the diaper. He sends a neutral, inquisitive glance in Dean’s direction. He’s trying to get more comfortable, pushing himself up on his arms, his hands against the seat, to lessen the pressure on his abdomen. Sam feels his dick swell and grow against his thigh, pressed down by the denim. Dean sighs and twists in his seat.
’Nah, I think I’m good for a while.’
Sam looks again. ’Okay.’
No way is he good. He’s turning rather pale, and there’s sweat on his brow. If he’s decided to pretend to be okay at this point, he must already have chosen to depend on the diaper. Sam is glad that the road is straight and almost empty. Because all his attention is really on Dean. He’s alternating between sucking in deep, shaky breaths through his nose, and biting his lip not to gasp. His thighs are shaking from pushing himself up, and he’s pressing one hand against his stomach while the other is frantically rubbing against his thigh. The gurgling sounds are coming constantly, now, and Sam can only imagine the kind of cramps that must be twisting his brother’s guts. Why doesn’t he let go?!?
’Aah, Sam, you gotta stop here, man, I have to get out! Now!’
Sam keeps his eyes on the road. ’No you don’t.’
In the corner of his field of vision, he catches Dean’s head whipping up, and Dean staring at him.
’Yes, I really, really do!’
Sam turns to him in exasperation, ’Why? Just go, already! Why wear diapers if you don’t use them?’
Dean’s facial color switches to bright red and he starts spluttering, but it quickly turns into a keening, and his whole body arches, tight as a bow.
’I just can’t, okay? That’s not why I wear them! Stop the car!’
Sam slams on the brakes. Before his disadvantaged brother can get out, he’s around to the passenger door, yanking it open, and pulling Dean out on his feet. He grabs him from behind and wraps his arms around him, whispering, ’I know that. I know why you wear them. And I think they are hot, too – you’re fucking irresistable in them! – but I want you to fill them with everything you’ve got. Just go, man. I know you’re dying to!’
Dean gasps, and leans back against Sam, not fighting. Sam pulls him tight up against himself, and wraps a big hand down and around his crotch, feeling the thick material under the clothes fit into his palm. Carefully, he puts his other hand against Dean’s stomach and presses.
Dean whimpers, and Sam can feel his whole body shaking, but finally he hears small, restrained, wet farting sounds start up. Oh yes. Dean moans and grabs Sam’s arm with both hands, squeezing it hard as his legs go soft beneath him, and Sam has to take his weight to keep him upright. It’s no effort. The sounds of Dean’s bowels finally releasing grow louder, and Sam can feel the increasing heaviness and thickness of the padding in Dean’s jeans. He turns Dean around and leans him up against the car, then gets down on his knees so his hands are free to move around his brother’s lower body, feeling with one hand how his insides gurgle and squeeze themselves empty, and with the other how the seat of his tight jeans bulges and fills. His legs are spread to make room for the huge mess, and it finally seems like the unstoppable flow comes to an end.
Sam gets up and puts his hands around Dean’s waist to unbuckle his belt.
’I know we’re in the middle of the road, but I don’t think you can sit back down like this without overflowing. Do you?’
Dean shakes his head against the roof of the car.
’Don’t move. I’ll get some clean stuff from the trunk.’
He fetches it quickly. After all, he’s been planning this for a long time. He has a clean-up pack ready in the bottom of his duffel. Carefully, he peels his brother’s jeans and boxers down, before pausing to feel the precarious fullness of the diaper. It’s quite a miracle it hasn’t gotten everywhere. Gently, he removes it and cleans Dean up. Then he puts a fresh diaper on him, and does his clothes back up. He struggles a bit with forcing Dean’s bobbing erection down into the soft paper nest. Dean stands up and opens the car door, sitting down sideways while Sam gets a shovel and buries the evidence of the incident. The sun is high in the sky, and they do need to move on. Before getting back in the car, Sam turns his back to Dean and pisses in the sand. It’s not easy, not because Dean is watching, but because he is still rather hard himself. Strangely, during the intensity of it all, it was like the urge for sexual gratification disappeared.
He turns the key in the ignition and looks at Dean, who’s fallen asleep in his seat again. He looks really peaceful, Sam thinks. Well, he is wearing the diaper. There will be plenty of opportunity to come all over it later – both inside and outside.