gripe session; grievance session
A mutual exchange of complaints, often informal and among peers. The compound 零し合い emphasizes the reciprocal nature of the complaining.
The drinking party turned into a gripe session.
I let off steam by having a grievance session with a colleague.
Standard kanji spelling for mutual complaining.
Mixed kana-kanji spelling; common in casual writing.
Compound of 零し (noun form of 零す 'to complain') + 合い (noun form of 合う 'to do mutually').