If there's a gentleman you want to kiss, don't hesitate. Any man would be delighted to receive an unexpected kiss from a lovely lady. It will make him feel good about himself. Just make sure to use your "randy radar" to tell whether to make it sweet and friendly, or go for something a wee bit naughty. Who knows, after you kiss him, he might kiss you right back!
And if a guy takes a chance and kisses you, always be polite, even if you don't particularly feel the vibe. It's the time for peace on earth, so show that goodwill towards men. After the kiss, smile, wish them a happy holiday, and politely excuse yourself on the pretense of needing to find your friend, or re-apply your lipstick.