We can use the term crack up in these ways - you crack me up or she/he totally cracked up.
It can refer to losing your nerve or composure but also losing control and being unable to stop laughing.
It happened to me a couple of times when I used to run training courses - somebody would say something and I'd just crack up and couldn't stop giggling. Once I even left the room - then, when I came back in, I started all over again.
You could laugh until it hurts or you cry but you just can't stop, Like this! It'll crack you up.
