Green’s Dictionary of Slang

(orig. US) a general excl. of agreement or approval, placed at the end of a sentence.

1865		B. Taylor letter 16 June in Taylor Life and Letters Bayard Taylor (1884) II xviii 434: I finished an article for the ‘Atlantic’ that day. As if I were not ‘a tool of the elements!’ ‘And how?’ as the Germans say (Americanicé — ‘You’d better believe it!’) [OED].
1889		C. Deveureux Venus in India I 109: ‘I’ve had, I dare say, many more men than you’ve had women!’ Frank and how!
1927		T.A. Dorgan in Zwilling TAD Lex. (1993) 14: Say that guy hit our ice box every night — And How!!
1930		E. Glyn Flirt & Flapper 25: Flapper: Dope — is what makes you forget to-day and to-morrow, but remember the day after that — and how!
1934		J. Franklyn This Gutter Life 50: ‘I do!’ he called back over his shoulder. ‘And how!’.
1944		Motherwell Times 2 June 6/3: Champions — And How! Congratulations to the boys of No 6 Company.
1947		I. Shulman Amboy Dukes 95: ‘Do you dance?’ ‘And how!’.
1953		J. Thompson Alcoholics (1993) 27: The young man said they did [i.e. get very drunk]. And how!
1967–8		C. Bukowski Notes of a Dirty Old Man (1973) 19: We had them by the balls. And how.
1973		B.S. Johnson All Bull 171: We made love for the first time that night; not for want of my trying earlier, but now she really did want it too, and how!
1982		H. Beaton Outside In I i: kate: Jesus Christ! Someone’s gonna get it! sandy: An’ how!
2012		R. Milward Kimberly’s Capital Punishment (2023) 310: [T]hose who want to leave the tent (and how).