When an actor, reporter, DJ or presenter/announcer, can't keep a straight face on camera, while on-air or while performing a scene, it's known as "corpsing."
This is a hilarious clip of actors Tim Conway and Harvey Corman BOTH corpsing during a skit on the Carol Burnett show. Corman especially is just not able to quite keep his face straight, throughout all of Conway's on-stage antics.


