Original Film Reel of Dating the Enemy

Origins
A 1996 Australian movie staring Claudia Karvan and Guy Pearce about a girlfriend and boyfriend who swapped bodies after having a fight, and had to learn how to walk a mile in each other's shoes.

Effects
If an unmarried couple that has fought (no matter how minor) watches the film, and makes physical contact during the viewing, the couple will swap bodies. The effect will last until the same couple views the film again on the night of a full moon, while maintaining skin-to-skin contact throughout the entire film, credits included. Any break in contact will render the effects permanent, and further attempts to reverse the process become futile.