Green’s Dictionary of Slang

an excl. used on seeing a special display of energy.

[1899		Daily Tel. 13 Nov. in Ware (1909) 261/2: To see Willie Edouin dance a hornpipe is a liberal education, and his official proclamation, ‘I trade in bumps. Oblige me by not saying, “What ho!”’ almost tempted an Ibsenite to smile].
1899		Mills & Castling ‘What Ho, She Bumps!’ 🎵 She roll’d about, and, fairly in the dumps, / I clung to the Captain’s bags, and cried: ‘What-ho! she bumps!’.
1900		Bulletin (Sydney) 28 Apr. 15/4: ‘I’m thinkin’ that you’d have to take Pat along wid you, too.’ What, ho! she bumps! Was anyone listening?
1902		‘Banjo’ Paterson ‘Johnny Boer’ in Rio Grande’s Last Race (1904) 166: Next day at dawn — ‘What, ho! she bumps’ — from somewhere in the rear.
1914		Sport (Adelaide) 10 Jan. 8/1: C. M. looked very nice with Fat A. What, oh, she bumps .
1918		‘Banjo’ Paterson ‘The Army Mules’ in Kia Ora Coo-ee 15 Mar. 9/1: Over the railways and over the dumps, over the Hun and the Turk, / You’ll hear him mutter, ‘What ho, she bumps’ when the Archies get to work.
1930		E. Waugh Vile Bodies 10: At first they had rather a jolly time about it, saying, ‘What ho, she bumps.’.
1932		(con. WWI) L. Mann Flesh in Armour 59: Skinny [...] sat down plomp on to the floor. ‘What O, she bumps,’ cried Tom.
1941		J.P. Carstairs [bk title] What Ho, She Bumps.
1951		Cusack & James Come in Spinner (1960) 330: Heavy shoes scraped on the tiled floor, glasses clinked and the cash registers tinkled incessantly. ‘What-oh she bumps!’ Blue edged along the wall towards the end of the bar. ‘Infiltration, them’s the tactics.’.