The holidays are about Advent/Hanukkah calendars and the countdown to Christmas Eve. For parents with college students, here is a more relevant number: Nine. That’s how many days are left until college boys return from the last day of finals. And for those who don’t know this drill, prepare to be enlightened.

There are five phases of the Christmas break.

Phase one. Welcome home! For the next hour, the Prodigal sons get a free pass. Countless transgressions — lost phone, wallet, car keys, fender benders, parking tickets, bounced checks — all shoved under the carpet. In return for this safe harbor, they talk freely about the semester and disclose anecdotes having nothing to do with their basket-weaving class. Information flows freely, assisted by a carb load in the form of muffins, cookies and brownies. Eventually mom’s focus turns to grades, bills, credit card charges, and those inappropriate photos someone mentioned to her on Facebook. Overheard in our house: “Tell me about the semester. Let’s start with Day One.”

Phase two: The big dig . Moms become archeologists. Dude’s clothes pile landed just inside the front door and includes much more than just clothes, if you know what I mean. Moms dive in and deconstruct the socks, party favors, receipts, 5-hour Energy bottles. Indiana Jones couldn’t solve some of these mysteries. MIA? Combs, razors, toothpaste. The Tide goes empty, the bleach runs dry. Manmouth Duo? Sandbar party? Owloween? That’s interesting … lipstick? Untouched by human hands — what mom left them four months earlier — trash bags, flashlight, first aid kit, sun screen, stamps.

Phase three: “Where are you going? You just got home!” They have mini reunions in neighborhood basements, Charlie Hoopers, P&L, party buses. This is networking the old-fashioned way – fist bumps, bromance hugs, chest bumps. The information stream just dried up and that river won’t flow until they need money for Spring Break. Phones suddenly have low batteries or have poor service when mom sends late-night texts. Change jars go empty. Cars with the full gas tank disappear. Rejoinder: “Later mom … I’m on vacation!”

Phase four: Dude’s a possum . Their nocturnal habits raise the tension. Lights left on, garage doors open all night, shoes tracking mud, curfews busted. Memo to Dude: This isn’t a hotel and there’s no mini-bar. Toilets clog, hot-water heaters blow and broadband is stretched to its limits. Entire countries invaded and defended. On Xbox. Promises to find a job, clean the car, wake up before noon – broken. Lucky Charms inhaled. The 5-hour Energy has left the building. Rip Van Winkle took its place.

Phase five: The honeymoon is over. It’s Dec. 26. You have 22 more days left until school begins again on Jan. 17. Time for tough love and then ask some important questions:

Who are those boys in the basement? They are boys, right?

Where’s my Christmas gift?

What’s growing on your face?

With any luck, slacker dude will utter these words: “I need to return to campus early. Like tomorrow.”

Parents … what’s your experience? Send me your story ( Mattkeenan51@gmail.com)and I’ll write a post-holiday piece.

Matt Keenan’s book, “Call Me Dad, Not Dude,” is available at thekansascitystore.com. Write to him at mattkeenan51@gmail.com.