Empty,
Crab actually refers to those of us in the RAF, a term the fishheads use. Believe it came about when the RAF first acquired its uniforms - they looked similar to crab paste, a popular tinned food in those days. But I digress...
Junglies are the Navy Seaking mates who get involved in wacky stuff with the marines etc, as opposed to be being tied to the ship 'pinging'. (apologies to the Navy brethren for this oversimplification).
As far as the streaming within the air force goes, most people come with the "all I've ever wanted to do is fly fast jets" approach. In most cases, as far as I've seen, those who show a preference to helos or multis, get it.
But Planks!!???