'Crack up' means to brag or boast.
You crack me up
Crack me upcrack me up
When the sun comes up ( but barely)
Perhaps you mean "crack you up." This is an idiom meaning to make you laugh a lot. The image is of you laughing so hard that you crack apart.
crack me up also there's hmu(hit me up)
CMTFU = Crack/ing Me The F**k Up
Crack the freak up (Polite form)
The idiom "crack someone up" means to make someone laugh or amuse them greatly.
Notch
crack into rant
The Crack-Up was created in 1945.