Don't try to be a hero. Unless you have no choice, there is absolutely no reason to be in a classroom on Friday. Thirsty Thursday is a collegiate institution: no matter how stupid you think it is when you roll up to campus freshman year, you will be a strict adherent by the time you're an upperclassman. If you aren't already a disciple of Thirsty Thursday, you will notice your peers starting to move Heaven and Earth to ensure that their Friday routine is limited to going from their bed straight back the bar.
Even the most studious among you will be lured out to the bar some Thursday evening for a karaoke night or a pitcher special, rendering yourself an academic embarrassment on Friday. There is no reason to fight the debauchery of the collegiate three-day drink week. When in Rome, partake of the beer bongs and body shots as the Romans do. If you aren't a heavy drinker, then reserve Friday as a day of leisure, when you take pleasant strolls through the abandoned high heels and piles of vomit left on sidewalks by your peers.