pretzel, n. — Green’s Dictionary of Slang

pretzel n.

[the shape]

1. (US jazz) a French horn; thus pretzel bender, a French horn player.

1926		E.P. Norwood Other Side of the Circus 236: A French horn is a pretzel.
1934		Charleston (WV) Daily Mail 31 July 6/8: Musicans have slang terms for every instrument [...] Pretzel – French horn.
1937		H. Brook Webb ‘The Sl. of Jazz’ in AS XII:3 181: pretzel. French Horn.
1949		Monteleone Criminal Sl. (rev. edn) 182: pretzel bender A player of the French horn.
1967		Ottowa Citizen (Ontario, Can.) 9 Dec. 63/4: Never [...] have there been gathered in one city so many [...] pretzel benders.

2. a German [the stereotypically Ger. foodstuff].

1944

D. Runyon Runyon à la Carte 200: Kindly do not refer to our people as krauts, pretzels, beerheads, Heinies.

do the naked pretzel (v.) [supposed resemblance to a SE pretzel, a crisp biscuit, baked in the form of a knot]

(US campus) to have sexual intercourse.

1991		Eble Campus Sl. Fall.
1996		Eble Sl. and Sociability 51: Slang provides numerous verbs for ‘to engage in sexual intercourse’. Among those recently in use on college campuses are bounce refridgerators, bump uglies, do the naked pretzel, get paid, knock boots, scrog, and scrump.