The effect of beer or any other alcoholic beverage to slow down brain fuction enough to convince a person that the song they are listening to (initially condidered to be crap) is actually moderately enjoyable. The effects usually continue to progress further by the person becoming convinced they can dance to the music, and thus finally resulting in the consumer screaming out onto the dance floor and expressing in a drunken slurr that... "Dude, this song F*$5KING ROCKS!"
Cousin to the beergoggles
After having a few drinks, JR began tapping his foot to the musical catastrophe of Pittsburgh Slim. The beerphones had just set in.