Green’s Dictionary of Slang

meadow mayonnaise n.

also meadow dressing
[euph. pun on bullshit n.]

(Aus./US) nonsense, rubbish.

[US]R. Bolwell ‘College Sl. Words And Phrases’ in DN IV:iii 234: meadow dressing, n. incredible nonsense.
[Aus]D. Stivens Jimmy Brockett 92: Jimmy Brockett was a terrible bull artist. I knew him pretty well and I chyacked him about it one day. ‘Look here, brother, [...] you bet I spread a bit of meadow mayonnaise around.’.
[Aus]Baker Drum.
Minneapolis Star (MN) 9 Feb. 32/1: He thought he was a bit of all right but the rest of us thought his talk was meadow mayonnaise.