Shoot 50s

Shoot 50s is another way to tell somebody to shotgun a drink.
Shooting fifty is also done in a group activity at 10:20, followed by some one calling "10:20" and everyone else saying "30 40" then shotgunning a drink (shoot 50).

guy 1: its almost time to shoot 50s

guy 2: okay

~time 10:20~
guy 1: 10:20
party: 30 40

(everybody shotguns a drink)