Green’s Dictionary of Slang

1. (US black) to dance uninhibitedly.

1928

C. McKay Home to Harlem 30: You could go to the Congo and turn rioting loose [...], fooping or jig-jagging the night away.

2. (US campus) to engage in homosexual acts.

1975

G. Underwood ‘Razorback Sl.’ in AS L:1/2 59: foopvt Engage in homosexual acts.