eat someone's ass out
Rebuke or scold harshly, as in Watch it or the sergeant will eat your ass out. This expression became wide-spread especially in the armed forces. [Vulgar slang; c. 1940]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.