Here is a Friday the 13th technical support bulletin directly from BMW-Munich:

"Herr must place five (for the 5 in X5) cases of Heineken in the trunk on the way home from the dealer. Once home, Herr must begin to consume the Heineken mit his Frau and complete the ritual together (X in the X5)."


Makes sense to me...remember its official, since you read it on the internet, when you explain it to her.