A euphemistic spelling of "hell." "Oh yeah?" said Tommy to the schoolyard bully. "Well, you can go to H-E-double-toothpicks!"
H-E-double-toothpicks
n. hell. (A jocular euphemism. It is not usually written and can be spelled a number of different ways.) Oh, H-E-double-toothpicks! I did it wrong again!