kill (oneself) laughing
To laugh hysterically and uncontrollably. The comedian had the whole audience killing themselves laughing. My ribs actually hurt from it! I was surprised by how funny my date was last night. I was killing myself laughing at some of her stories!
kill yourself laughing
be overcome with laughter.ˈkill yourself (ˈlaughing)
(British English, informal) laugh a lot: It was a very funny video. We killed ourselves laughing from beginning to end.He just stood there, killing himself laughing.