backslapping
noun [ U ] uk/ˈbækˌslæp.ɪŋ/ us/ˈbækˌslæp.ɪŋ/
（高声的）互相赞扬;相互祝贺
a noisy expression of happiness and positive feelings, usually showing admiration for a shared success
There was a party after the ceremony where much drinking and backslapping went on. 庆典之后举行了晚会，晚会上人们开怀畅饮，相互祝贺，甚为热闹。