Green’s Dictionary of Slang

1. the penis; occas. the vagina (see cit. 1970).

1954		(con. 1920s–30s) J.O. Killens Youngblood (1956) 124: Y’all ain’t been playing with your wee-wees, is you?
1970		B. Aldiss Hand-Reared Boy 32: I unbuttoned my fly-buttons and showed my rosy little wee-wee to Sheila. [Ibid.] 33: Cricket and Red Indians [...] interested me more than female wee-wees.
1980		A. Maupin More Tales of the City (1984) 49: You’ve lost your wee-wee, remember? All you can do is smile bravely.
1991		C. Hiaasen Native Tongue 259: His wee-wee had withered from 10.4 centimeters to 7.9. centimeters in its flaccid state.
2005		J. Stahl I, Fatty 31: Boy’s so fat he can’t see his weewee.

2. see wee n.