Green’s Dictionary of Slang

Earl n.1

[echoic]

used in phrs. pertaining to vomiting.

In phrases

call Earl (v.) (also talk to Earl)

(Aus./US) to vomit.

[US]Baker et al. CUSS 93: Call earl Vomit.
[US]Eble Campus Sl. Nov. 1: blow donuts – vomit. Also [...] call Earl, talk to Earl.
[US]Eble Campus Sl. Sept. 1: barf – vomit [...] call the Irishman, call (or talk to) Earl, hug the toilet, pray to the porcelain god.
Online Sl. Dict. [Internet] call Earl v 1. to vomit.