When an attractive woman seduces an intoxicated male and sleeps with him. Early the next morning the woman will have her very unattractive friend take her place in bed, and wait until the man wakes up. He will then look over at who he thought was a smokin hotty and then start freaking out
the effect that alcohol(particularly large volumes of beer) has in rendering a person who would one would ordinarily regard as unattractive as sexually alluring.
Even with the beer goggles on, she was still remarkably plain.
A "beer goggles bitch" is an ugly woman you pick up at the bar at 2:30 AM when you are totally plastered. When you wake up, you can't believe what your eyes are showing you that you dragged home!