let off steam
GIVE VENT TO ONE'S FEELINGS, speak one's mind, speak out, sound off, lose one's inhibitions, let oneself go, use up surplus energy

[TahlilGaran] Dictionary of Contemporary English ▲

let off steam
[British, American & Australian, American & Australian]
to do or say something that helps you to get rid of strong feelings or energy.
Meetings give people the chance to let off steam if something has been bothering them for a long time.

After a long journey, the kids need to run around a bit and let off steam.

I've told her she can call me and talk any time she wants to blow off steam.

[TahlilGaran] English Idioms Dictionary ▲

let off steam
get rid of your extra energy or strong feelings by doing some activity
He was very angry at first but he has let off steam and has calmed down now.

[TahlilGaran] English Idioms Dictionary ▲

let off steam
v. phr.
1. To let or make steam escape; send out steam.
The janitor let off some steam because the pressure was too high.
2. informal To get rid of physical energy or strong feeling through activity; talk or be very active physically after forced quiet.
After the long ride on the bus, the children let off steam with a race to the lake.
When the rain stopped, the boys let off steam with a ball game.
Bill's mother was very angry when he was late in coming home, and let off steam by walking around and around.
Bill had to take his foreman's rough criticisms all day and he would blow off steam at home by scolding the children.
Compare: BLOW ONE'S TOP, LET GO⁶.

[TahlilGaran] English Idioms Dictionary ▲