corpse

1. (intransitive, slang, of an actor) To laugh uncontrollably during a performance.Examples: "The rest of the day and the week were spent blocking and learning the lines. The only drama was the predictable one of being ticked off for corpsing. Rupert was quite as bad as me when it came to giggling and the tea-party scene which took place between Rupert, David Parfitt, Piers Flint-Shipman and I, was too much."; "There were still moments when she would halt suddenly, like an actor stranded in the middle of the stage, lines forgotten, staring goggle-eyed and making fish-mouths...Corpsing: that was the word."; "Poor Damian corpsed and almost forgot his next lines. The director gave him a terrific lecture, and Alan caught hell from stage management."intransitiveslang

2. (transitive, slang, of an actor) To cause another actor to do this.slangtransitive