That is the only explanation I can conceive of, and it seems to be the prevailing theory. I am given to understand that it is a common tradition near the end of the year, for one to kiss another under the mistletoe.

[ She tries to sound clinical about it, but the way she wavers a little on kiss probably belies that. ]

As for the stories, merely that its effects were widespread and rather indiscriminate. At least we are already acquainted with one another.