i wanted to know expressions/idioms like that one - when something makes you laugh a lot - in other languages! it doesn't have to be translated directly (losing your head) but expressions/idioms that means the same in your language! thanks! :)
Cześć Alex!
You know, Pękaj ze śmiechu! doesn't sound too good. If it was in the indicative form it would be ok, but the imperative form just sounds weird.
This is why I prefer your second option "Zrywaj boki ze śmiechu!" or I can suggest you the third one: "Śmiej się do rozpuku".