Green’s Dictionary of Slang

double-barrel n.2

[note Cleland, Memoirs of a Woman of Pleasure (1748–9): ‘My hot-mettled spark [...] loaded for a double-fire, recontinu’d the sweet battery with undying vigour’]

of a man, more than one orgasm in a single session of sex.

Show quotations
[[UK]Bridges Homer Travestie (4th edn) I 159: The whoring rascal, safe and sound, / Prepares to fire a double round].
[Ire]A. Roberts Rasherhouse 83: But inanyway, he used to pay me three hundred pound, so he did. For nuttin’ special like, just a double barrel.’ 'A double wha’?’ ‘Double barrel! That's when they want to come twice like, ya know?’.