crack me up
when someone says something funny and you start laughing uncontrollably you say "YOU CRACK ME UP!"
person 1: he is planning world freckelation!
person 2 who is laughing uncontrollably: dude! u crack me up!
person 2 who is laughing uncontrollably: dude! u crack me up!
cracking me up
Making me laugh
You are cracking me up!