How does the expression go?

“Act like you’ve been there before.”

I first heard it applied, decades ago, to guys breaking into some sort of celebratory spasm when scoring touchdowns. Spiking the ball, throwing it into the stands, dancing. Whatever.

The idea is, behave as if whatever you just did successfully … is not unusual. Or perhaps is just part of what you intend to do. Don’t act as if you just knocked out somebody.

Which brings me to the Division Series playoffs in Major League Baseball. And who partied hard … and who did not.

Three of the four winning teams made spectacles of themselves after the final out and broke out champagne. Even though the division series is only the first of three steps in the playoffs.

The Phillies, Giants and Rangers all were in full-spray mode in the clubhouse after mob scenes on the field.

The Yankees had some champagne but didn’t go crazy in the clubhouse — and did little more than shake hands on the field. Which is how winning a division series ought to be celebrated.

The Phillies had least reason to go crazy. They have played in the last two World Series. They ought to know how much work is ahead. Management should have made a point of handling it the way the Yankees did.

The Giants … well, they ought to aspire to more than this. The Rangers we can perhaps forgive, considering the franchise had never won a postseason series.

Still, celebrating after one round gives the impression that you aren’t quite sure you will have another chance to celebrate. It sends out the wrong signal.

Which was why the Yankees’ low-key reaction was impressive. They indicated they understand that they have two more series to win. The job is only partially completed. Newcomer Marcus Thames told reporters, “That’s three down, but we’ve got eight [victories] to go.”

Anyway, let’s say the Phillies,  Giants or Rangers win the World Series. If they celebrate a league championship the way they did a division-round victory, and we must assume they will, that would make for four dogpile/champagne celebrations in about four weeks — or two champagne baths too many.

Celebrate clinching a playoffs berth, because that’s about six months of work. Celebrate the World Series, because you are champions of ball. But the rest … you still have work to do. No other sport celebrates a job one-third finished.