Why freshmen at one high school give their mothers a goodbye kiss on their first day

For incoming freshmen at Bishop Kelley High School in Tulsa, Oklahoma, it's hard to imagine a more mortifying first day.

All the seniors surround their cars and don't let them out until they do one specific thing: give their mothers a goodbye kiss.

"We hold the car, we hold the car door, preventing it from opening," one senior Bishop Kelly student told CBS News.

It can also be a father or a guardian. The point is that someone needs to be publicly thanked with a peck on the cheek.

All the freshmen know this is coming. In fact, it is now a 26-year school tradition.

Before this, seniors still greeted the freshmen on day one. But back then the "welcome" was a little more biting. It was based more on pranks. That is, until the class of 2001 decided to be kinder while also making the newbies feel just a little bit uncomfortable.

"I wouldn't have wanted to kiss my mom as a freshman," said Sister Mary Hanah, the school's president.

Sister Mary Hanah said she can relate to the reluctance, but she thinks that Biblical rule, to honor thy mother and father, made the top 10 list for a reason.

"And you know who the happiest people are in this whole thing? ... The mothers," Sister Mary Hanah said. "This is a big moment for them, especially if this is their first child or their last child."

It is a rite of passage. Which is why at Bishop Kelley, they celebrate the milestone — that sweet, fleeting moment between a parent and child — with a couple hundred screaming seniors.

"The moment you drive off after dropping them to school is when it hits you," said one parent.

Added another: "He gave me that kiss and I saw him leave and that meant I have to let go."