Green’s Dictionary of Slang

1. to have sexual intercourse with.

1896		Sheaves from an Old Escritoire 86: Here’s a go [...] The toff’s lady is a treat [...] almost as tight as those two school misses we blocked last Monday!
1909		Joyce letter 3 Dec. to Nora Barnacle, in Ellman Sel. Letters (1975) 182: I know that I was the first man that blocked you but did any man ever frig you?
1909		G.R. Bacchus Pleasure Bound ‘Ashore’ 10: He had blocked his captain’s wife, and then murdered the captain.
1922		Joyce Ulysses 711: And if I was married hed do it to me and I promised him yes faithfully Id let him block me.
1928–41		in G. Legman Limerick (1953) 69: There was a young girl of Rangoon / Who was blocked by the Man in the Moon.
1937–84		Partridge DSUE (1984) 96/1: since ca. 1890.

2. (N.Z.) to gang rape; also as n., a gang rape; thus put/go on the block, of a young woman, to be subjected/subject oneself to gang rape.

1973		Truth (Wellington) 4 Dec. 5: Home had told the girl: ‘You’ve got between now and the time I finish this cigarette until you go into the bedroom and go on the block.’ [DNZE].
1976		Press (Wellington) 23 Mar. 2: Mongrel Mob members accused of gang rape [...] He heard someone say, ‘We’ve got a honkey on the block’.
1987		L. Jones ‘Sour Grape at Ambury Farm Park’ in NZ Listener 117 23: She came around. She was shaking. I gave her a smoke. She looked like she had been blocked. There were 20 or 30 [Mongrel] Mobsters around the stage.
2003		McGill Reed Dict. of N.Z. Sl. 25: to put/go on the block [Ibid.] 25: block A pack rape, or a female subjected by a group of men to serial sexual activities [...] From 1970s.