Acronym for "Laughing My Fucking AssHole Shut" typically used in Internet postings to express a response of great hilarity. A more advanced, powerful term than its predecessors LMAO and LMFAO, it should be used with care to prevent injury.
I was LMFAHS when my proctologist attempted to perform my colonoscopy.
OMFG, that video had me LMFAHS!
LMFAHS @ Stewie Griffin!