Green’s Dictionary of Slang

1. (also jang-jingo) the penis.

1948		in Randolph & Legman Ozark Folksongs and Folklore (1992) I 516: (Well,) I fucked her four times in the morning [...] With my jingo, jang-jingo, jang-jingo [...] a fragment of a long piece sung near Huntsville, Arkansas, in the 1920s.
1966		Trimble 5000 Adult Sex Words and Phrases.

2. the vagina.

1966		Trimble 5000 Adult Sex Words and Phrases.
1972		R.A. Wilson Playboy’s Book of Forbidden Words.
1982		Maledicta VI:1+2 (Summer/Winter) 131: Vagina […] jampot, jaxy, jelly roll […], jing-jang, joxy.

3. sexual intercourse.

1966

Trimble 5000 Adult Sex Words and Phrases.