Green’s Dictionary of Slang

1. (orig. US) to belch.

1932		J.L. Kuethe ‘Johns Hopkins Jargon’ in AS VII:5 330: burp—v.—to belch.
1936		Mencken Amer. Lang. (4th edn) 564: Above all, he enriches the vocabulary of action with many new verbs and verb-phrases, e.g., to burp, to neck, to gang [...] and so on.
1940		Writer’s Forum Mar. 26: He was puffing and looked as if he might burp and she hoped he wouldn’t.
1960		E. De Roo Big Rumble 27: He was known as Pepsi because he could burp whenever he felt like it.
1983		M. Keane Time After Time (1984) 47: She [...] sat sipping and burping her way through a health drink.
1987		B. Chatwin Songlines 84: Hanlon burped and said ‘Beg pardon!’.
1999		N. Cohn Yes We Have No 326: She was a martyr to gas all her life and now she never even burps.
2000		Guardian G2 12 Jan. 14: Suddenly they both sit up and burp.

2. to make someone, often a baby, belch .

1952		W.R. Burnett Little Men, Big World 57: Gas, I told you. He’s got to be burped better.
1975		J. Wambaugh Choirboys (1976) 306: We’ll have to burp him, for chrissake.

3. (Aus., also burp a rainbow) to vomit.

1966		M. Rumaker Exit 3 and Other Stories 165: Watch he don’t burp on you!
1967		F.J. Hardy in Great Aus. Lover Stories 63: Euphemisms for vomit [...] include spue, burp, hurl, the big spit, the long spit.
1969		A. Buzo Rooted I iii: Remember the time he got sick at Davo’s twenty-first and went for the big spit? He said to me ‘Jees I feel crook’, and then he [...] shoved his head out the window and burped a rainbow.