Green’s Dictionary of Slang

1. (US black) to grab and squeeze a woman’s breast.

1992

(con. 1920s) F.M. Davis Livin’ the Blues 72: You expected a jane to have a standard set equipment, and occasionally [...] you’d grab ’em and squeeze (we called it ‘hunching’).

2. (US) to betray, to doublecross.

1952

(con. 1948) G. Mandel Flee the Angry Strangers 261: ‘Whaytta you mean? Dincher tryin to hunch me?’ [...] ‘He’ll blast you for looking cockeyed, you big dope.’.