Green’s Dictionary of Slang

1. (also shillaluh) the penis.

1838

‘Rory O’More Had A Hell Of A Bore’ in Rambler’s Flash Songster 12: Now Rory, be aisy, the girls would all cry, / When first his shillaluh they did espy.

2. (US) a police officer’s truncheon.

1939		Howsley Argot: Dict. of Und. Sl.
1960, 1975		Wentworth & Flexner DAS.
2000		(con. 1940s–60s) Décharné Straight from the Fridge Dad.