Green’s Dictionary of Slang

battering piece n.

the penis.

1748–49		Cleland Memoirs of a Woman of Pleasure (1985) 82: I guided officiously with my hand, this furious battering-ram, whose ruby head presented nearest the resemblance of a heart. [Ibid.] 163: Louisa [...] directed faithfully the point of the battering piece.
1789		Burns ‘Come rede me, dame’ in Complete Works (1986) 349: Nidge me o’er the nyvel! Come lowse and lug your battering ram, And thrash him at my gyvel!
1826		letter in Duberman ‘Writhing Bedfellows’ in Journal Homosexuality (1980/81) VI Fall/Winter 88: You roughen the downy Slumbers of your Bedfellow—by such hostile—furious lunges as you are in the habit of making at him—when he is least prepared for defence against the crushing force of a Battering Ram.
1832		Satirist (London) 26 Aug. 278/4: General Nugent arrived at the seat of war, and brought his battering-ram to bear upon the walls; but it was the Duchess’s bomb that did the business.
1860		Boudoir ‘The Three Chums’ in Pearsall (1969) 379: The battering ram of love had to be vigorously applied before a breach was made sufficient to effect a lodgement.
1870		Cythera’s Hymnal 73: My father’s yard measure / I view with great pleasure, / Such a bloody great battering ram!
1880		‘La Rose d’Amour’ in Pearl 14 Aug. 11: I took hold of my battering-ram and strove to force an entrance.
c.1886		Tilly Touchitt 36: The more formidable battering engine about [...] to be brought to bear against the little breach.
1890–1904		Farmer & Henley Sl. and Its Analogues.