Green’s Dictionary of Slang

jigging bone n.

the penis.

c.1720		‘The Original black Joke. Sent from Dublin’ 🎵 I’ll play a tune on the jigging bone / Of your coal black &c.
1890–1904		Farmer & Henley Sl. and Its Analogues.
1896		Farmer Vocabula Amatoria (1966) 53: Canal, m. 1. The penis; ‘the jiggling-bone’.