Green’s Dictionary of Slang

Julius Caesar n.¹

the penis.

1890–1904		Farmer & Henley Sl. and Its Analogues.
c.1904		A. Crowley Snowdrops from a Curate’s Garden 22: She shot off my well-oiled plenipo and was immediately split up from the fork to the shoulders by the giant callibistris of Lord R...y, whose affection for a buttered bun is only equalled by the size of his Julius Caesar.