In the mainstream cultural references are seemingly random. But, really it is an art form. You learn by participating and being a part of the crowd.

Exposure
Ideal 
Practice
Learned
Habits
Friends
Social

The issue for some (most) who are not the target demographic is that once terms get into the mainstream, they are no longer relevant. So, you're still out of the loop. It doesn't have to be difficult. Just don't be late to the conversation.  

~ Dawn aka Hat Girl