L.l.a.f.
L. l. a. f. is when you're laughing so hard it looks like you’re trying to laugh your face off. It usually happens when you're wasted, high, or just plain ridiculous.
I laughed like a fuck when my friend told me my dog tried to eat my shoes.
At the party, I laughed so hard I fell on the floor.
My brother laughed like a fuck when I told him my math teacher fell out of a window.