Green’s Dictionary of Slang

Bronx cheer v.

[Bronx cheer n.]

(US) to make a loud derisive noise, as if breaking wind.

[US]Lubbock Morn. Avalanche (TX) 11 Nov. 8/5: A down-front dozen of high school students hooted and Bronx cheered joyfully.
[US]Shamokin News-Dispatch (PA) 29 Nov. 4/1: Police Judge Taggart [...] fined the man $15. Ryals tossed bnack his head and issued a robust Bronx cheer. Angered, the judge added 10 days in jail. Again Ryals gave the salute. The judge increased the sentence to 30 days. Ryals Bronx cheered again.
[US]E. Dahlberg Those Who Perish 104: Two loafers standing at the edge of the curb bronx-cheered and yelled: ‘Melamed, Melamed — hey, rabbizin!’.
[US]B. Appel People Talk (1972) 45: A drunk bronx-cheers everybody, salesmen and spectators.
[US]S. Morgan Homeboy 314: The opening bars of ‘Fascination’ were Bronx cheered through a saxophone.