Green’s Dictionary of Slang

(US) to whip, to punish.

1872		‘Mark Twain’ Screamers (1875) 97: Don’t ever let me catch you chewing tobacco before breakfast again, or I lay I’ll blacksnake you within an inch of your life.
1882		Nat. Police Gaz. (NY) 22 Apr. 3/3: [T]he Voodou curse that was put on old man De Courcy by an abused and liberally ‘black-snaked’ negress.
1890		Salt Lake Herald (UT) 17 June 3/1: The human brutes that abuse the horses that they drive [...] ought to be blacksnaked.
1897		Kansas City Dly Journal (MO) 10 Jan. 4/4: Satank presented his letter [...] and of course got a very cool receotion [...] One wagon boss blacksnaked him.
1905		Eve. Statesman (Walla Walla, WA) 11 Aug. 1/5: [headline] Farm Hand Blacksnaked. Stranger given a severe whipping.
1917		Honolulu Star-Bulletin (HI) 30 Oct. 6/2: A Cincinnati preacher who prayed for the repose of the Kaiser’s soul has been blacksnaked.
1935		H.L. Davis Honey in the Horn 173: His uncle blacksnaked him for coming home late.