tell a thing or two

tell a thing or two  {v. phr.},  {informal}

To tell in plain or angry words; scold.

When John complained about the hard work, his father told him a thing or two.

If Bert thinks he would like to join the army, I'll tell him a thing or two that will make him change his mind.

Compare:

BAWL OUT,

GIVE A PIECE OF ONE'S MIND,

TELL OFF,

THING OR TWO.