Green’s Dictionary of Slang

1. (US) the anus.

1969

‘Iceberg Slim’ Mama Black Widow 4: My wand must cry deep in your bunger, my dear boy.

2. a male homosexual.

1966		Trimble 5000 Adult Sex Words and Phrases.
1972		B. Rodgers Queens’ Vernacular 17: The man who fucks in anal intercourse, as opposed to the one who is fucked [...] bunger (dated).