Last December, at dinner with another couple, I encountered a dreaded holiday season scenario: Between the main courses and the coffee, my friends handed me a beautifully wrapped box. Inside was an incredibly thoughtful gift.

However, I hadn't gotten them anything. I hadn't even thought about it! These were friends, but not, I thought, close enough friends to be exchanging gifts with.

So I lied. I told them I had gotten them something, but it was on its way in the mail. Then I went online and scrambled to find something.

That may have been a poor decision, says Diane Gottsman, an etiquette expert and owner of the Protocol School of Texas. "If someone gives you a gift and you don't have one in return, the last thing you want to do is make an excuse that sounds inauthentic," she says.

I'm hardly the first person to opt for this tactic and won't be the last. But if you don't want to be caught unawares next time, here's what etiquette pros say to do when you receive an unexpected gift.

What to do when you receive an unexpected gift

Start by giving the gift you've received its proper due. "Accept the gift graciously, smile and say, 'Thank you so much for thinking of me,'" says Gottsman.

You may also remark how thoughtful the other person has been or express that you're surprised to be receiving something from them. "Whatever you say, keep the tone light and lively. The joy is giving the gift for the giver," she adds.

From there, you can decide whether or not to reciprocate with a gift of your own, a move that etiquette experts say is entirely optional. If you do, don't feel like you have to run out and grab something right away, or give the illusion that their gift is already in transit, as I did.

"You can follow up with a gift in a day, a week, or even a New Year's gift," Gottsman says.

And don't feel pressured to go tit-for-tat with someone who may have given you a gift that would be out of your normal price range, says Elaine Swann, a lifestyle and etiquette expert and founder of the Swann School of Protocol.

"If you want to reciprocate, reciprocate in a manner that works best for your budget," she says.

One way to make sure you're keeping things in check: giving cash. Swann, who recently published a guide to holiday tipping and gifting in partnership with Zelle, says giving someone the gift of digital cash is perfectly within the bounds of good etiquette.

"Money is one of the best gifts because you know for certain it will be used," Swann says.

Naturally, you don't want to make it look like you're paying someone for their gift, the same way you might send them money if they covered lunch. Rather, use the app's "notes" feature to indicate that the cash is a gift and to personalize it for the recipient, says Swann.

"Here's something toward that set of golf clubs you've been eyeing. Or that designer bag. Or the cooking classes you've been wanting to take," Swann suggests as examples. "It feels as though you've put some thought behind it because you've taken the time to make that note."

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