Btfsplk
Joe Btfsplk is a character in the comic strip Li'l Abner. He is well meaning, but is the world's worst jinx, bringing bad luck to all those around him.According to cartoonist Al Capp, Btfsplk is a rude sound. During a public lecture by Al Capp, his demonstration of this phatic sound was to close your lips, but leave your tongue sticking out, then to blow out air, which is also called a 'razzberry' or Bronx cheer.
"How else would you pronounce it?" -- Al Capp.