The point during a night of drinking alcohol when one is caught between drunkeness and sleepyness. One must make the decision to rally and continue drinking or wave the white flag of surrender aka be a bitch and pass out.
Kyle: "Dude I'm in serious Beergatory right now"
Nate: "Rally time Bitch" *hands Kyle a PBR*
Taco Bell Drive Through Lady: "What would you like tonight"
Marlowe: "Not sure yet, we have a few people in Beergatory here"