Sox, the 3 Y/O chubby arctic fox sits, being strapped into his carseat by his mother, wearing a poofy dry pink diaper under a sea-green onesy and blue overalls, she opens the passenger-side door and buckles in.

Mom: You stay dry this time, we don't want to change your diaper at the mall again, and more importantly, we don't want the car smelling like your stinky butt the whole ride!

Dad: C'mon, hun, be easy on the boy.

Mom, whispering, though still audible to Sox's keen ears: Do you want the car to stink like shit for half-an-hour?

Dad: Well, maybe I do

Mom, sighing: Don't be nasty, Gruff. 

They both give a wholesome chuckle, Sox smiles dopefuly, like every other tubby cubby, not a care in the world, the autumn wind from his half-open window and the soft rumbling of the heavy running car engine leaving him tired and limp, sinking into his seat while his eyes rest half-closed, so snug and content, infact, that he didn't even notice the dull pain in his bladder, the pressure building without his knowledge, his muscles loosten as the front of his diaper swells with the salty smelling liquid, and the sound of spraying running piss as audible as possible.

Mom: Did you have an accident already, Sox?

Sox: N-No, no.

Mom gives *That* look (You know the look)

Sox: Y-Yes, sowwy momma, just numbew 1 dough.

Mom: Oh, well if it's just number 1, you're good.

Sox's chest fills with ease, knowing he dodged a bullet as he relaxes back, his diaper slopping with the sound, and feel, of total sogness.    
At most 10 minutes pass by, or so Sox thinks, being a baby he doesn't quite have a keen sense of time, his belly begins to rumble, and even Sox knows it's not just the car or the rocky road, but moreso the 4 bottles of milk he's already had today, he, in his comforted state, releases a not-so-subtle, though completely adorable, wet fart.    
Mom looks back, anxiously, only soon after smelling the rank blast of gas.

Mom: Oh god Sox, we need to get you out of bottles, soon.

Dad: Aww, don't be mean, he just gets that from me.

Mom: Yeah, I know that, smelling your farts all night.

Sox gives a laugh, knowing that he'll be as naughty as his daddy someday, his rumbly belly only reminding him of that fact, he feels pressure in his gut, what he assumes to just be another fart, he thought wrong...    
After giving a brave, heavy push, he instantly feels a flood into the butt of his diaper, pure liquid diarrhea, thick and milky, so much that only half of it is able to absorb into the padding, but now the floodgates can not be closed, his butthole opens so widely that an unimpeded rush of liquid mess, lasting just 9 seconds, fills his diaper, forcing up the front and the sides, mom immediately pinches her nose, even with the window open the smell radiates the car.

Mom: What the hell did you do?!

Sox, looking proud of his actions: I dih-it bettew den you coudda!

Dad just smiles, feeling proud of his quick-learning son.

Mom just sighs and looks away form the 2 nasty boys.

Sox sits, putting all his weight against his mess, causing it to mush around, as he quickly falls into a deep nap, sucking his thumb and smirking, releasing multiple more spurts of mess in his rest, causing his mommy to suffer in the smell, and his daddy to sit there proud, even farting a few times himself and adding to the smell.