箍たがが外はずれる

expression, ichidan verb, intransitive verb

lose all restraint; go to excess; become disorderly

Idiomatic expression derived from the image of a barrel hoop coming off, causing the staves to fall apart. Used when someone's self-control breaks and they act wildly, excessively, or without inhibition. Often carries a negative or critical tone.

• 酒さけを飲のむとタガが外はずれて、いつも騒さわいでしまう。

  When I drink, I lose all restraint and always end up making a racket.

• 彼かれは上じょう司しがいないと箍たがが外はずれて、仕し事ごとをさぼってばかりだ。

  When the boss isn't around, he loses all self-control and just slacks off.