Green’s Dictionary of Slang

to speak in a cloying sentimental manner; thus gushing n., an extravagant display of feeling or sentiment; also as adj.; gushy, over-emotional, and gushingly adv.

1863		Dundee Advertiser 17 Nov. 3/4: Gushing. Modern novel writers seem to have an idea of love-making peculiarly their own.
1864		M.E. Braddon Henry Dunbar 47: She is one of those girls whom friends call ‘gushing;’ and she called Byron a ‘love,’ and Shelley an ‘angel’.
1867		‘Artemus Ward’ Artemus Ward in London in Complete Works (1922) 477: Do not, at least, do so [...] until all the ‘gushing’ feelings within you have been thoroughly subdued; until, in short, your hide is of rhinoceros thickness.
1870		Sportsman (London) 23 June 2/1: Fleet-street has invented ‘royal’ literature for itself, and whenever royalty is mentioned gushing writers begin ‘boo-booin’’ .
1872		‘Mark Twain’ Roughing It 143: We were ashamed that we had gushed so.
1883		Sheffield Indep. 2 Dec. 13/6: [from Punch’s Alamanac] They count gushing all humbug. Don’t gush, ma’am, don’t gush [...] Do gushing give o’er.
1885		‘’Arry on the Merry Month of May’ in Punch 16 May 229/1: Premiers and Patriots may gush, / But wot ud become of their Shows if it weren’t for the larks and the lush?
1891		Sheffield Dly Teleg. 8 July 6/5: Gushing Critics. Really the silly gush of the some of the radical newspapers [etc.].
1905		Marvel 23 Dec. 677: You needn’t gush, you know, or any rot of that kind.
1916		C.J. Dennis ‘Ginger’s Cobber’ in Moods of Ginger Mick 56: But don’t make no mistake; ’e don’t gush none, / Or come them ‘brother’ood’ remarks too thick.
1928		J. Agate Gemel in London 57: A young lady at a concert gushed up to me with a copy and asked me to autograph it.
1936		W.R. Burnett King Cole 35: The two Baylor girls gushed and [...] told Read at great length how delighted they were to meet ‘our wonderful Governor’.
1946		S. Jackson Indiscreet Guide to Soho 57: Even the trade journals gush with super-colossal enthusiasm about each new canned offering.
1978		L. Kramer Faggots 225: ‘It’s gorgeous!’ The Divine Bella, their correspondent on the spot, gushed up to Fred.
1989		A. Higgins ‘The Bird I Fancied’ in Helsingør Station and Other Departures 151: Margaret was staring and silent, Betsy gushing.
1999		K. Sampson Powder 97: She was so gushingly favourable about a band who hadn’t even been interviewed by NME or Select.
2000		Indep. on Sun. Rev. 19 Mar. 57: The guy has talent to burn [...] I hate to gush, but he really did have.
2018		G. Gilmore Base Nature [ebook] ‘Getting all gushy about some secretary’s reasons for knocking off her boss?’.