Green’s Dictionary of Slang

(a) to charge excessively.

1822		Westmorland Gaz. 27 Apr. 4/5: Coachee [...] you needn’t be afeard of laying it on pretty thick .
1829		Reading Mercury 6 Apr. 4/5: I intend to lay it on my customers pretty thick, or in other words, to tip it to them pretty stiff in my charges.

(b) to exaggerate; to make an excessive fuss.

1840		E. Howard Jack Ashore III 273: It does my poor broken heart good to hear ye cuss that sodger – go it again, my daffydown-dilly, and lay it on thick.
1858		A. Mayhew Paved with Gold 122: ‘You are a-laying it on,’ he answered impertinently; ‘one would think I was everything bad to hear you talk.’.
1901		E.W. Hornung Black Mask (1992) 230: You did lay it on.
1936		W.R. Burnett King Cole 81: ‘Wouldn’t he lay it on when he got home! [...] ‘Men like that,’ he’d say to his wife and son; ‘I surely told them a few things they didn’t know before’.
1943		R. Llewellyn None But the Lonely Heart 96: ‘I mean a stork, Tiger,’ Henry says, laying it on a bit.
1977		B. Jackson Killing Time 177: I was laying it on just for the fun of it.
2010		(con. 1973) C. Stella Johnny Porno 188: They put the hammer to her. ‘Turn informant or get used to munching muff the next dozen years’ [...] They laid it on thick.

(c) (orig. US) to criticize, to berate.

1910		O. Johnson Varmint 240: You laid it on pretty strong.
1926		Van Vechten Nigger Heaven 120: Now Dick, you’re laying it on pretty hard.
1940		F. Sargeson ‘Boy’ in A Man And His Wife (1944) 8: My father heard me answering my mother back, and oh gee if he didn’t lay it on.
1978		R. Price Ladies’ Man (1985) 163: Don’t lay it on me.
1980		J.L. Gwaltney Drylongso 225: From then on she really laid it on Miss Donnelly.

(d) (US black) to seek a verbal or physical confrontation, to hit.

1936		Big Joe ‘Rootin’ Ground Hog’ 🎵 I’m a rootin’ ground hog babe, I roots everywhere I go / Lay it on me boy, it’s bad!
1967		K. Kolb Getting Straight 144: You’re flipping, and I should have had the guts to lay it on you straight when it first started.
1970		T. Parker Frying-Pan 12: I picked up the cue [...] I was just going to lay it on him.

(e) to inform, to pass on information.

1959		A. Zugsmith Beat Generation 137: I’m going to lay it on you.
1975		D. Goines Inner City Hoodlum 111: Call Amos’ ol’ lady and lay it on her.
1980		E. Folb Runnin’ Down Some Lines 244: lay it on See break it down.
2002		‘Touré’ Portable Promised Land (ms.) 159: We Words (My Favorite Things) [...] Lay it on me. Layin in the cut. Let’s get it on.
2010		K. Richards Life 267: ‘You Got the Silver’ [...] was one of the first ones I wrote entirely by myself and laid on Mick.
2015		S. King Finders Keepers (2016) 105: Go ahead. Lay it on me.