Green’s Dictionary of Slang

apples n.

1. the female breasts [the rounded shape; the term has survived but became more a euph. than sl. by 20C].

R. Tofte (trans.) Montreux V5: [Cupid] was wont to respose himselfe betwixt those two beutifull Apples, they being farre more pretious, then that golden fruite of the Hesperides.
[UK]T. Carew A Rapture (1927) 7: O’re all the Garden, taste the ripened Cherry, / The warme, firme Apple, tipt with corall berry.
[UK]W. Drummond ‘Fragment’ II 276: Vpon her brest two aples round did grow, / Vith tops of strawberries more white than snow.
[UK]E. Pugh Street in Suburbia 11: She was wot I call an apply-dumply sort o’ woman, wi’ the apples artside.
[US]Sara Martin ‘Squabbling Blues’ [lyrics] I got peaches in my pantry, / Apples hanging on my shelf, / I got peaches in my pantry, / Apples hanging on my shelf, / I’m getting doggone tired of sleeping by myself!
[US] in Randolph & Legman Ozark Folksongs and Folklore (1992) I 375: Apples be ripe, and nuts be brown, / Petticoats up and trousers down!
[US]Monteleone Criminal Sl. (rev. edn).
[US]Maledicta III:1+2 25: A woman has bosoms, a bust, or a breast, / [...] / They are towers of ivory, sheaves of new wheat; / In a moment of passion, ripe apples to eat.
[US]E. Folb Runnin’ Down Some Lines 141: There are a number of vernacular terms that refer to a woman’s breasts as big, tasty, touchable, and formidable – grapes, apples.

2. the testicles.

[UK] ‘Adam’s Root’ in Bang-Up Songster 8: Two pretty apples hung from it below!
[UK] ‘He Did It Before My Face’ in Ri-tum Ti-tum Songster 33: Then down he pulled his buckskins new [...] And dangled two large apples.
[UK]‘Neaniskos’ Priapeia Ep. lxxiv 71: Thief [...] If thou shalt steal my large apples, I will give thee the apples* of the breeches (*Apples meaning testicles).
[US]Maledicta IV:2 (Winter) 195: [Testicles] are commonly called balls or ballocks, stones or dusters, apples or nuts.

In phrases

how do you like them apples?

see separate entry.

like two apples in a bag (adj.)

(orig. US) a ref. to well-formed buttocks, irrespective of sex.

T. Van Mersey Talk [Internet] Similes. like two apples in a bag: a woman with a lovely rump.
love apples (n.) [note Fr. pomme d’amour; Ger. liebesapful, the fruit of the tomato]

the testicles.

Rambler’s Mag. June 227/2: Besides the common name of Arbor Vitae [...] the very name of Poma Veneris [i.e. apples of love] [is] frequently given by authors to the fruits of this tree.
[UK]‘The Tree of Life’ in Fake Away Songster in Spedding & Watt (eds) Bawdy Songbooks (2011) III 293: Some late virtuoso this tree to improve, / Have cut off its fruit, called the apples of love.
[UK]Farmer Vocabula Amatoria (1966) 29: Balloches (les), f. The testes; ‘love-apples’.
[US]C. Himes Crazy Kill 8: Anoint The Love Apples With Father Cupid’s Original adam ointment.
[US]H. Max Gay (S)language.