Rule is a guideline for alcohol
consumption that goes like this:
"Liquor before beer, nothing to fear. Beer before liquor, never been sicker."
The placement of the 2 relationships doesn't matter whether one's before the other, as several drunks have argued it as long as they rhyme you've got the idea of the Rule.
Sonia forgot the Beer-Liquor Rule on a Friday night and missed her hair appointment the next morning.