Here's why we call the open-mouth smooch a 'French kiss'

Kissing helps reduce blood pressure and boosts your self-esteem.

(CNN)Every great love story culminates with a kiss.

It typically comes toward the end, with a desire that's been building over the course of an hour and some odd minutes. We hold our collective breath as the couple before us gaze into each other's eyes (you know, the look) and begin to lean into a -- sometimes awkward or sloppy but always heartwarming -- French kiss.
But why are these specific kisses labeled French? In honor of International Kissing Day, we decided to look into the matter. Here's what we learned:

French kissing became popular after WWI

    The term "French kiss" entered the English vernacular in 1923, Sheril Kirshenbaum writes in her book "The Science of Kissing."
    No one really knows the exact reason why we use the term, but it was likely adopted by Americans who traveled to France and kissed French women, who were more comfortable with a bit of tongue action, says Kirshenbaum.
    Naturally, the term "French kiss" developed.
    Still, it took a while for the term -- and even the practice -- to catch on in the United States.
    It wasn't until after World War II that Americans felt comfortable enough to French kiss each other, says Kirshenbaum. She credits American servicemen who served in Europe with bringing the kissing style home.
    Remember that iconic photo of a US sailor kissing a woman in Times Square? Exactly.
    An American sailor passionately kisses a white-uniformed nurse in Times Square to celebrate the long awaited-victory over Japan. August 14, 1945.