Falas is anything u do in the inappropriate time,u might enjoy doing it,makes u laugh,or drifts u away from what ur really supposed to be doing at that time.

For example,Ur having an exam in a few hours and ur chatting with a friend online on the what the news mentioned about the weather next week.

Another example for Falas is that,u being so eager to know what is Falas and reading all this when u were supposed to do something else,is considered itself "Falas" and making u a "Mofles" or "Moflesa".