Green’s Dictionary of Slang

dry fuck n.

[SE dry + fuck n. (1a)]
(orig. US)

1. (also dry rub) a simulated act of sexual intercourse, without penetration and usu. without removing the clothes.

[US] (ref. to late 19C) N. Kimball Amer. Madam (1981) 231: The johns got a dry rub standing up.
[US] ‘Betty Co-Ed’ [comic strip] in B. Adelman Tijuana Bibles (1997) 58: Dry fuck ... 50$.
[US]H. Miller Tropic of Capricorn (1964) 104: Maybe you’ll [...] get a dry fuck.
[US]Goldin et al. DAUL 63/1: Dry rub. (P) Body contact, in wrestling or ‘horseplay,’ patently homosexual.
[US]Trimble 5000 Adult Sex Words and Phrases.
[US]E.E. Landy Underground Dict. (1972).

2. in fig. use, something tedious or disappointing.

[US]T. Williams Letters 177: If only Margo could get something of this quality into ‘The Project’ [...] It is a dry fuck, really [HDAS].

3. (gay) anal intercourse without any form of lubricant.

[US]Maledicta III:2 231: He also may or may not know the following words and expressions: [...] eye-doctor (where eye = anus), dry fuck (without penetration, or without KY or other lubricant such as vaseline or Crisco – mostly for fist-fucking).
[SA]K. Cage Gayle.