Mistletoe

Source
To acquire this item, simply type /kiss while targeting a Winter Reveler who are located in most inns during the Feast of Winter Veil. Winter Revelers will randomly give you a stack of five of Mistletoe, or a  after typing /kiss. Only the Winter Revelers in the inns participate.

You will also receive a debuff preventing you from getting another of these gifts for one hour. This hour is real time, so you can switch characters and come back an hour later.

Achievements

 * Two achievements, one per faction, require the use of mistletoe.
 * Bros._Before_Ho_Ho_Ho's_(Alliance) uses nine. The most difficult target is in a low thirties area.
 * Bros._Before_Ho_Ho_Ho's_(Horde) uses only three, but two of the targets are on Northrend.
 * These can only be done during Winter Veil, you do not get credit for using mistletoe on the achievement targets out of season.