Dying to death
You're not dead yet but well on your way.
(Hears a funny joke and laughs so uncontrollably that he can't breathe)
"Oh my God!! I'm dying to death!"
"Oh my God!! I'm dying to death!"
dying of death
dying of death doesn't mean you are actually dying because there needs to be a reason why your dying.
i am dying of death because thats soo funny