Green’s Dictionary of Slang

toast v.

[SE toast, to make a speech when drinking someone’s health]

1. (US black) to recount a lengthy epic poem, usu. based in the pimping or underworld experience; thus toasting n.

[US]L. Durst Jives of Dr. Hepcat (1989) 6: At a party one of the ace hi gets up to toast.
[US]Milner & Milner Black Players 23: Men would boast and toast and lie and goad each other into gales of laughter and rounds of handslapping.
[US]Lou Reed ‘The Last Shot’ [lyrics] Here’s a toast to toasting and I’m not boasting.

2. (W.I.) of a disc jockey, to perform one’s own lyrics to the background of a reggae song, usu. in a dub (no lyrics, only bass and rhythm lines) version; thus toasting n.

[UK]D. Hebdige Subculture 38: Power was at home here [...] channelled through a battery of home-made speakers. It was present in every ‘toasted’ incantation.
[UK]R. Hewitt White Talk Black Talk 115: The toasting [...] is the oral art form of reggae music. [Ibid.] 123: You have to have a rough voice for toastin’.
[US]C. Cooper Female Sexuality in Lyrics of Bob Marley and Shabba Ranks 2: 1980’s violence versus 1970’s peace [...] toasting versus singing.
[US]G. Pelecanos Night Gardener 35: Beanie Man toasted from the house stereo.
[UK]D.S. Mitchell Killer Tune (2008) 55: The King’s wailing chants as he toasted onstage.

3. (US Black) to defeat.

Lord Shafiyq ‘My Mic Is On Fire’ [lyrics] I’ll roast ‘em, toast ‘em, post ‘em where the sea dwells.
Notrious B.I.G. ‘Party & Bullshit’ [lyrics] Nigga, I toast ya, put fear in your heart.
MC Lars ‘We Have Arrived’ [lyrics] Take these haters down then I toast them like some Eggos.