An idiom meaning to lose restraint or decorum and go overboard — to cut loose or behave without restraint.
忘年会で羽目を外しすぎて、翌日上司に叱られた。
I cut loose too much at the year-end party and was scolded by my boss the next day.
飲み会では楽しむのもいいが、羽目を外さないように気をつけてください。
It's fine to have fun at parties, but be careful not to get carried away.
若者たちが深夜に騒いで羽目を外したため、近所から苦情が出た。
Because the young people made a ruckus late at night and went overboard, neighbors complained.
久しぶりの休みで羽目を外す気持ちもわかるが、後のことも考えよう。
I understand wanting to cut loose after a long time off, but think about the consequences.