Something that doesn't make sense and sounds like utter nonsense can be described as codswallop, also, in some places of devon, there are cults that use the walloping of a cod as a method of induction into their sect...

Used to denote the fallaciousness of any statement/idea.

Orig. Old English, where the 'cods' referred to the cock and balls, thus codswallop was jiz, spunk, cum, semen.