Jus shitted on myself, just like LMFAO or ROFL but if something is funnier than that then you pretty much just shit on yourself so if something hella funny you put, JSOMS.
One day i heard some dude saying "joom" at a certain beat so i started looking around to see why he was saying that, it was because some ladies huge perfect tits were bouncingup and downeverytime he said "joom".