What does LMBO stand for in texting?

Laughing my butt off
(US, Canada, Internet, Internet slang, text messaging) Laughing my butt off or laughing my balls off.

What does LMNO stand for?

laughing my nuts off
Phrase. LMNO. (Internet slang, vulgar) Initialism of laughing my nuts off; used to indicate great amusement.

What does LMHO stand for?

Laughing my head off
(Internet slang) Laughing my head off.