Green’s Dictionary of Slang

the testicles.

1542		T. Elyot Bibliotheca n.p.: Cliterini, the cullions or stones of a man.
1599		R. Perceval A dictionarie in Spanish and English 67: Cojúdo, m. he that hath great cullions or stones, that which is not gelded but hath his stones.
1640		W. Lithgow The rare adventures, and painefull peregrinations 347: [A] Masse-Priest [...] had gotten in his owne Parish, three Widdowes and their three severall Daughters with child, and a [...] and for this his Luxurious Cullions was brought to Dijon to be Executed.
1653		Urquhart (trans.) Gargantua and Pantagruel (1927) I Bk II 322: The fire which I had cast into the lap of my poultry roaster burned all his groin, and was beginning to seize upon his cullions.
1661		G. Rogers Horn Exalted 8: In our brain theres a belchose and cogliones lying lovingly close together.
2002		(con. WWII) R. Mooney Father of the Man Prologue: ‘Balls,’ Conklin explained, ‘sometimes referred to as nuts, gonads, stones, rocks, cods, cullions, bollocks, family jewels, or – for the learned among us – testicles or testes.’.