SPAF is a meaningless word. It's flexible, versatile and utterley meaningless; it can apply in any situation. If in doubt, say 'SPAF', and the situation somehow becomes bleakly funnier. www.spaf.tk details the invention and rise of SPAF, as a meaningless diversion invented to pass the time by so-called 'gifted' teenagers.
Sadly, with the invention of lol
, SPAF is now mostly obselete.
Person 1: *high-speed flow of technobabble, including several jargon words you will never have heard before*
Person 2: (when expected to comment) Uh... SPAF?
Person 2: (when bored and in public) *shouts at random strangers* SPAF!