Laughing So Hard That I Farted.
LSHTIF! What made you think that they are dating?
An acronym standing for "Laughed So Hard That I Farted."
It should be used in place of related acronyms such as "LOL", "LMAO", "ROFL", etc.
Through text:
Bro 1: Hey bruh bruh! Our bro Rufus is hitting on my mom in the kitchen!
Bro 2: LSHTIF! Shut it down, bruh!