Green’s Dictionary of Slang

1. the male chest.

1891

G.R. Sims ‘Tottie’, Dagonet Ditties 126: In my ‘East and West’ Dan Cupid / Shot a shaft and let it there.

2. a vest [note SE vest is an undergarment; SAmE vest is a waistcoat].

1906		Sun. Times (Perth) 21 Oct. 4/8: But not content with taking one, / Another those poachers pinched, / And swift (in the words of the slangful gun) / My ‘East and West’ ‘half-inched’.
1923		J. Manchon Le Slang.
1935		A.J. Pollock Und. Speaks 35/2: East and West, a vest.
1946		St. Vincent Troubridge ‘Some Notes on Rhyming Argot’ in AS XXI:1 Feb. 46: east and west. The vest (Origin uncertain, but probably English.) Probably American. The vest is an undergarment in English.
1953		Berrey & Van den Bark Amer. Thes. Sl. (2nd edn).
1969		S.T. Kendall Up the Frog.
2002		B. Kirkpatrick Wicked Cockney Rhy. Sl.

3. (also east west) the female breast.

1978		Maledicta II:1+2 (Summer/Winter) 118: Elsewhere Aylwin lists a few more ‘Vulgarities’: [...] words for breasts (brace and bits, east and west, Jersey City, thousand pities, towns and cities, fainting fits).
2003		B. Dark Dirty Cockney Rhy. Sl. 50: east west breast.