Green’s Dictionary of Slang

snonk n.

[? snozzle n. (2) or similar sn— terms meaning the nose + conk n.1 (1)]

(Aus.) the nose.

[Aus]J. McNeill Old Familiar Juice (1973) 65: bulla: Bloody blackhead...hundred times I’ve squeezed it outer me snonk, ’n it still keeps coming home.