'TIS THE SEASON when a whole lot of motorists are going to drink and drive.

There's a reason why December is National Drunk and Drugged Driving Month. If people are going to drink and then get behind the wheel, the prayer is that they at least do so responsibly.

But how to tell what's responsible alcohol consumption?

That, unfortunately, has become a whole lot harder with all the new products on store shelves, such as alcohol-infused whipped cream.

Whose crazy idea was it to add alcohol to whipped cream?

People are getting blasted by shooting that stuff straight into their mouths.

And don't even get me started on Four Loko, the alcoholic energy drink, a/k/a "blackout in a can," which some headcases stockpiled before the FDA ordered it taken off store shelves.

Thinking about all this gave me the idea to write a column suggesting that people consider having "one and be done," or at the most "have two and be through."

I'll admit the sayings sound a little goofy.

But a catchy slogan seems to me to be one way to remind people what their limits are without being preachy.

I'm not a teetotaler. I like a glass of wine as much as anyone. My strategy is to drink as soon as I get to an event. I always have something to eat - preferably protein.

And an hour before I'm planning to go, I lay off the alcohol.

But there just are no hard-and-fast rules when it comes to how much alcohol you can safely get away with drinking during a holiday party.

What works for me might not work for you.

There are so many variables: a person's weight, gender, what they're drinking and whether they've eaten recently.

All these factors influence a person's blood alcohol level even though they have consumed the same number of drinks as someone else. (And this doesn't even take into consideration how much a squirt of caramel-pecan or strawberry colada Whipped Lightning on top of an Irish coffee ups your alcohol consumption.)

Of course, the best choice is to abstain from drinking anything. But that's not much of a party for some of us.

The vigilant folks at Mothers Against Drunk Driving (madd.org) have created a coupon you can download and offer to your friends to let them know that you will be the designated driver.

MADD's slogan for this is even cornier than the ones I dreamed up: "Frolic with glee. Tonight I'm DD."

But at least it gets people thinking ahead of time about who should stick to plain tonic water while everyone else is sipping on bubbly.

Because "the designated driver is not the one that is least drunk - 'I didn't drink much so I can drive,' " warned Carol Heimerl, a victim advocate for MADD's Southeast Pennsylvania affiliate. "The best thing is to have a plan before you even start."

Here are some other ideas from MADD. Yeah, you might have heard them before, but they bear repeating:

_ Arrange for a limousine or car service.

_ If you're throwing a party, have nonalcoholic drinks available and stop serving alcohol an hour before the party ends.

_ Don't serve underage drinkers.

_ Have a backup plan in case your original safe-transportation plan falls through.

And here's a final cliche that might bring the message home before you refill your glass:

The life you save may be your own. Happy holidays.