thrash on someone

thrash on (one)

To berate, upbraid, or criticize one. I made a fairly innocuous comment about the situation, and everyone on the forum started thrashing on me for it! You don't need to thrash on the entire team for one person's mistakes.
See also: on, thrash
Farlex Dictionary of Idioms.

thrash on someone

in. to scold, criticize, or berate someone. She’s always thrashing on her roommate.
See also: on, someone, thrash
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • thrash on (one)
  • tear (one) a new one
  • tear someone a new one
  • rail at
  • rail at (one)
  • be all over
  • be all over (one)
  • be all over somebody