http://www.spiritualcuriosity.com/curiosity/rock_music.htm

Backmasking

Something like subliminal songs but deadlier as this backmasking is done by summoning a devil to speak on the song. Here is one famous song by The Eagles – Hotel California

Forwards: 'There were voices down the corridor, thought I heard them say, welcome to the hotel California.'

Backwards: 'Yeah Satan, he organized, oh, he organized his own religion. Yeah, when he knows he should, how nice it was delicious, he puts it in a vet he fixes it for his son which he gives away.'

FACTS: Indeed, the hotel in Hotel California is not in fact a hotel. The 'California' is a street in Los Angeles where the first Satanic Church was built, headed by Anton Szander Lavey, author of the Satanic Bible. Many major musicians were said to have attended this church, including Mick Jagger of the Rolling Stones

Aliester Crowley (very popular in the rock music world). Crowley gives instructions to the Satanist:
". . .train himself to think BACKWARDS by external means, as set forth here following.
(a) Let him learn to write BACKWARDS. . .
(b) Let him learn to walk BACKWARDS. . .
(c) Let him. . . listen to phonograph records REVERSED
(d) Let him practice speaking BACKWARDS. . .
(e) Let him learn to read BACKWARDS. . ."
(Aleister Crowley, Magick In Theory And Practice)