I heard/read from youngsters that they use 꿀잼 a lot. (or 개꿀잼 for that matter.) This prefix 개(dog) literally can be used with every word in Korean, like effing in English. of course 존나 잼있어 is extremely frequent. And another thing that comes to mind is as you say in English "I pissed myself laughing" we say "너무 잼있어서 오줌쌀 뻔 했어" but this is somewhat corny. I think people say "너무 잼있어서 뒤질뻔 했어/죽을 뻔 했어/ 기절하는 줄 알았어... etc etc." I guess you'd know how this type of talk goes on.