Green’s Dictionary of Slang

tamping n.

[tamp v. (1)]

(US prison) a beating.

[US]J. Black You Can’t Win (2000) 157: Anybody that didn’t crawl for Corbett got a good ‘tamping.’.
[US]M. Braly On the Yard (2002) 215: He’s got you figured for five tampings this last year.