In your Champagne, that is. Or your sparkling wine, whatever fits your budget and your palate!
If, per chance, you and your special someone fail to finish your sparkling beverage, just drop a silver (really any metal should do) spoon into the neck and store it back in the refrigerator. Ensure the spoon has a little wiggle room above it and is not stuck in place.
In my experience, the bubbles will last a good 24-hours, though for taste, it is best consumed within a few hours!