Lafin
Laughing so hard you sound like a goat that got hit by a truck. You can't stop and you don't want to. You just yell 'LAFIN' because you're too stupid to think straight.
He told the class his pants were on fire and I was LAFIN so hard I snorted my juice.
She said her cat talked to her and I was LAFIN so loud the dog started barking.
He texted me a picture of a banana and I was LAFIN so hard I fell off my chair.