Like a goshdarn Christmas miracle, mistletoe allows us to smooch strangers in the name of holiday cheer. Sounds easy, right?

Be careful— there are rules. But first, some history:

Why do we kiss under mistletoe?

According to the book, Prose Edda (an Icelandic collection of four sections), mistletoe owes its fame to Norse mythology. Here is the abridged story of mistletoe, according to esteemed CultureMap historians:

Frigga, the goddess of love, had a son, Balder, the god of the summer sun (and presumably baldness and/or Babar the elephant). One night Balder dreamt of his death. He was hella freaked out and told his mom, natch. Frigga freaked too because she figured that without Balder, Earth would die since he’s the sun god and all.

In a fit of overprotectiveness, Frigga made every plant and animal pinky-swear they wouldn’t hurt Balder. Loki, god of evil and frenemy of Balder, noticed that Frigga overlooked mistletoe (some say because mistletoe was too young) and fashioned a blade with mistletoe at the tip. Loki then got someone to shank the hell out of Balder, and he died.

Luckily for us, mistletoe felt totes terrible about the whole sitch and, with Frigga’s help, brought Balder back to life. Frigga’s tears became the white berries of the bush. To ensure that no one would get mistletoe-shanked again, a shared kiss became a token of the promise. So, basically, a mistletoe kiss is a promise not to shank each other. Shagging, however, is encouraged.

Mistletoe Etiquette:

• Mistletoe should be fresh, organic and, of course, free range. Nothing kills the holiday spirit more than finding out that produce is the result of a dire caged existence. (Luckily, you’d have a tough time finding anything other than wild mistletoe as the parasitic plant feeds on other trees. Romantic.)
• Fake mistletoe is completely out of the question and is roughly 3.78 times as tacky as fake Christmas trees.
• Never confuse mistletoe and holly. Holly has red berries. Mistletoe’s are white.
• Refrain from attaching mistletoe to your pants. You may think you’re clever, but everyone else thinks desperate, DESPERATE. This person is really desperate.
• For a convincing random mistletoe kiss, have a friend hang it on the ceiling beforehand. Make sure you’ve kissed at least one other person under it to conceal your true intentions.

If you DON’T want to smooch under the mistletoe, try these tactics:

• Talk about mistletoe’s not-so-romantic aspects. The word 'mistletoe' (Old English mistiltan) may be related to the German mist for dung and tang for branch, since mistletoe can be spread in the feces of birds moving from tree to tree. (Gross!)
• Complain of open mouth sores.
• Mention that consuming mistletoe causes diarrhea. However, you can always sex up its digestive implications, as anyone who has seen Batman Returns can attest. (Batman, on roof with Catwoman: "Mistletoe can be deadly if you eat it." Catwoman: "But a kiss can be even deadlier if you mean it," and she licks his face.)
• If he still persists, crush up the mistletoe berries and put them in his cider.

Happy scheming.