If it hasn't happened already, there will be a time when you are at a party, minding your own business, and suddenly handed a loose bag from boxed wine — most likely Franzia. What are you to do with said bag of wine? Simple: slap the bag.

Slap the bag has become a standard at college parties across the nation. Don't freak out if you have never heard of it before or frankly just don't know how to participate, we've got you covered. Here are the (un)official rules to slap the bag.

Whether it's an organized game at a party, a mandatory action for entrance, or just a dude walking around with a bag of wine, the rules are generally the same. Begin by grabbing the stopper while somebody holds up the bag high and put your mouth on the stopper — maybe consider the repercussions of this first

Loosen and unscrew the stopper to let the wine flow out and start chugging. This part is important: make sure you drink for a respectable amount of time. If the crowd feels that you didn't take a big enough drink initially, they may heckle you until you do the whole darn thing again. 

When you've taken a sufficient enough drink, twist the stopper closed. You'd be amazed how many people forget that part. Once the wine has stopped flowing, open your hand up and slap the side of the bag like you would high five your beer pong partner after a win. Don't slack on the slap. It's not called "pat the bag" or "caress the bag," so really give it everything you've got. 

So there you have it, slap the bag — the game that proves that college students can even make wine unclassy. If you ask me, I would definitely rather slap the bag over taking a pull of cheap vodka any day.