Green’s Dictionary of Slang

1. a German homosexual; also as adj.

2003

K. Cage Gayle 52/2: Ada n. 2. a German homosexual (There are a lot of Ada tourists in South Africa these days.) [1950s].

2. a homosexual who cannot find a sexual partner.

2003

K. Cage Gayle.

3. the buttocks [initial letter of arse n. (1)].

1992		Isaacs & McKendrick Male Homosexuality in S. Afr. 79: I’d like to pomp her up the Ada, but she looks so Dora’d.’ [Ibid.] 247: Ada, the buttocks area, usually in relation to base relief in tight pants [Simes:DLSS].
2003		K. Cage Gayle.