Every morning, Chris O’Brien takes his son Cooper outside to the front of their Southern California home while his wife, Hailey, makes breakfast inside.

The pair settles into Cooper’s little toy car and watches vehicles pass. Chris, 32, uses the time to point things out — “That’s a blue truck, that’s a green van, that’s a yellow bus” — turning it into a playful way to connect with his 1½-year-old son.

In July, Chris decided to share the quiet ritual on TikTok. He’d already been posting about his photography side business, but thought this sweet father-son moment was worth capturing. When he uploaded a short clip of Cooper sitting on their driveway curb, he never expected what happened next.

“I figured, well, I’m out here every single morning anyway, so maybe I’ll just start posting as part of the routine,” Chris tells PEOPLE exclusively.

But what began as a simple pastime quickly grew into a viral phenomenon. Within weeks, millions of people were tuning in daily to watch “Coop on the Stoop,” as Cooper plopped down on the family’s curb, rain or shine.

“I didn’t even come up with the name — someone commented it, and it just kind of organically became what it is now,” Chris says.

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From there, the trend snowballed. Fans across the world began recreating the videos — from a couple outside a pub in England to NFL teams and fellow TikTok creators.

Part of the charm, Chris believes, lies in its simplicity. Viewers even invented their own “stoop code”: a dry curb signals a good day, while a wet one means bad.

“My wife always says the people in the comments are the funniest in the world,” Chris says with a laugh. “But in reality, it’s just my son. Everything is one take — I pull out my phone, film for a second, and then put it away so I can be with him. If he sits on the curb, that’s what people see. If he doesn’t, that’s what they get. It’s never a performance.”

As the series evolved, so did its signature. Somewhere along the way, Chris began signing off with a simple line: “And we’ll be here.”

At first, it was just a casual way to end the clips. But when Chris skipped it once, followers instantly noticed. The phrase stuck — transforming into the series’ unofficial tagline and, for many viewers, a quiet source of comfort.

That comfort also took on deeper meaning when Chris and Hailey, 32, revealed in a video that amid the viral attention, Hailey’s father had passed away.

“It’s not just what I say at the end of the video anymore,” Chris explains. “It’s also like, hey — if you’re grieving, if you’re sad, if you’ve lost someone — we’re here for you, the same way people have been here for us.”

Hailey, who is also pregnant with the couple’s second child, says it felt important to be transparent. “While everything online looked peachy and fun, behind the scenes, our hearts were breaking,” she tells PEOPLE exclusively. “People don’t always see that side of social media, but being honest about our reality felt necessary.”

As for the future, the couple has no grand plan for Coop on the Stoop — and they prefer it that way.

“He’s eventually not going to want to sit there and watch cars, and that’s okay,” Chris says. “The goal was never to force it. We’re just sharing our everyday lives — two full-time working parents with a toddler and another baby on the way. There’s no secret recipe here. We just want it to feel organic.”

For now, the parents are savoring the joy it’s brought and preserving the memories for Cooper to cherish someday.

“He’s going to have a built-in fun fact for life,” Chris jokes. “And we’ve saved so many comments and videos because I can’t wait for him to see it all when he’s old enough to understand.”

Hailey adds: “We’re even putting together a keepsake box with little things people have sent, kind comments, hats — just reminders of this time. One day, he’ll be able to look back and see not just how crazy it all was, but the heart behind it.”

And while Chris may be the one on camera with Cooper, he insists the credit belongs to Hailey too.

“It’s me in the videos, but it’s Hailey who is the driving force behind our family,” he says. “She’s carried so much — being pregnant, raising Cooper, helping him thrive, and supporting me while we navigate everything that’s come our way, all while grieving. The reason I know what I’m doing as a dad is because of her.”