John handed his baby to the redheaded young woman just as the director began yelling "Lights, camera, action!" The redhead – a petite woman of barely 25 – smiled into the camera and began speaking.
"My son used to cry at night when his nappy got wet, and it often gave him rashes too. But then I discovered Nappiness, the best diapers in existence. Now we all get a wonderful night's sleep!" The camera zoomed in to show Sam's butt for around three seconds before the lady dressed him in a Nappiness diaper. Then they cut to the Nappiness logo, and a kiddy voice – Dean's – said, "Nappiness! For every baby's happiness!"
"That's a wrap!" shrieked the director, and the cameras stopped rolling. The redhead handed Sam back to John and smiled at him before going off for a drink of water.
John held his baby boy up to his face. "Good job, Sammy!" he praised. "Now you're going to be on TV."
"Oo ga waga?" asked Sam, patting John's nose with his chubby little fists.
"No, Sammy, you can't have your bottle now," Dean said. "You gotta wait till we get home."
Sammy pouted, before pulling John's nose.
It hurt a little, to see the redhead posing as Sam's mother in the ad. If Mary had been around she could have done the part, but she wasn't. Sam was never going to be in his mother's arms again. Instead a redheaded lady got to be his mother for thirty seconds on TV.
John sighed, but his sadness dissipated at the sight of Sam reaching for Dean. He handed the kid to his brother, smiling. Those boys. They were all he needed. They kept him sane, they were the reason he woke up each morning.
The director handed John a check, paying for Sam and Dean's services. John accepted it, took Dean's hand and decided to buy them ice-cream.
"Yeah," grinned Dean. John tried not to pay any attention, but he too was hiding a smile behind his newspaper.
"YOU PUT ME IN A DIAPER COMMERCIAL? YOU SHOWCASED MY BARE ASS FOR THE ENTIRE COUNTRY TO SEE?"
Dean grin grew. "Well, in our defense, your ass did earn us a lot of money."
"YOU PROSTITUTED ME!"
"Sam, calm down," instructed John, putting down his newspaper. "The director saw us in the park and decided you were the cutest baby he'd ever seen. He just had to have you in his ad."
Seventeen-year-old Sam groaned. "I hate you. Both of you. You – you betrayed me. My own family betrayed me."
"A lot of old ladies who saw the ad used to come up to us when we were out," Dean said. "They used to go all, 'Aren't you the baby from the diaper commercial? We loved your ass!'"
"No they didn't," John muttered, trying to prevent another explosion. He failed.
"DEAN! Old ladies don't say 'ass'!"
"Sure they do. And they loved yours."
Sam flushed. "I'm so writing you out of my will," he grumbled.
John grinned. "I guess it wouldn't hurt to mention they paid us $2000 to show your bare ass on TV?"
And that, ladies and gentlemen, is the story of why Sam Winchester blushes and hides his face every time he sees a diaper commercial on television.