Green’s Dictionary of Slang

1. the penis.

1654		New Brawle 15: You’ll be in your Dissembling Fitts again anon, and none but Ned the Butcher must come and cure thee again with his lusty [...] Diddle.
c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Diddle [...] also something else, to be guessed, not written. I slipt her a Jorum of Diddle.
1882		Cremorne II 35: I had only seen the innocent little ‘diddles’ of the black picaninnies.
1890–1904		Farmer & Henley Sl. and Its Analogues.

2. the vagina.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1948		(con. 1927) in Randolph & Legman Ozark Folksongs and Folklore (1992) II 617: D is for diddle, that never grows stale, / For there’s nothing so good as a nice piece of tail.

3. (also diddling) sexual intercourse.

1893		‘Bob Sterling’ Town-Bull 10: The pleasure of a good hard diddle.
1902		D. St John Memoirs of Madge Buford 51: We would have a nice, quiet little diddle all by ourselves.
1905–07		Bawdy N.Y. State MS. n.p.: COMMON OLD FASHIONED FUCK, – – – – – – $2.20. DIDDLING ON THE EDGE of the BED, – – – $3.10. DRY BOB, – $1.50.
c.1935		‘Betty Co-Ed’ [comic strip] in B. Adelman Tijuana Bibles (1997) 57: Diddling on edge of bed one foot on floor – $2.00.
1939		H. Miller Tropic of Capricorn (1964) 103: It means a quick diddle and he doesn’t want to diddle her any more.
1941		in G. Legman Limerick (1953) 47: Her pimp, a young fellow named Biddle, / Was seldom hard up for a diddle.
1966		B. Jackson Get Your Ass in the Water (1974) 213: D is for diddle, it never grows stale, / there’s nothing so good as a nice piece a tail.
a.1968		‘School Ma’am on the Flat’ in G. Logsdon Whorehouse Bells Were Ringing (1995) 54: She’d gave him a little diddle that fairly made him dance; / She said he’d have to marry her, now what else could he do? / He surely couldn’t turn her down, since she’d gave him that good screw.
2000		F. Kellerman Stalker (2001) 541: Right after the murder, Bederman broke off the diddling with Lark, but the two of them were still tangled up.

4. masturbation.

1938–46

in G. Legman Limerick (1953) 274: You get three in one— / A ducking, a douche, and a diddle.