This is idiom of laughing hard, i’m right? Or there any other meaning?
It was said after one funny situation.
I’ve never heard it before, however, google returns a single result for a post on a reddit thread which does appear to mean “we continued to laugh hard”.
There is an idiom “split one’s sides laughing” which means “to laugh very hard”. My guess is that the reddit result is a bit of hyperbole, made up by ImpulsiveZombie for the sake of the reddit post, not a well-known idiom.