Is it legal in the state of Washington to possess and carry a colapsing baton or do in need something dumb like a CCW permit? If it is legal are there any limitations on how I can carry it?

As I understand it, you have to complete a certified course in the use of the collapsible baton before you can carry it.  Unfortunately, there are not a lot of places that offer the instruction.

Title 9.41.050 forward will give you some good insite. The old law specifically stated that a Concealed Weapons Permit holder could not carry knives, clubs (batons), rifles, etc. legally under their CWP license. Now the license is called a Concealed Pistol License and the respective, revised law mentions only pistols being carried/concealed and no other items.
That would lead me to believe you cannot carry an ASP under your CPL.
Unfortunately, I couldn't find anything directly pertaining to collapsible batons.
From what I've heard, jwar is correct. It requires a specific class and permit.
I do know one thing for fact: Edmonds, WA passed a city statute forbidding the sale, trade, and ownership of collapsible batons. LEO's are exempt. Just call-up Adventure Sports and ask if they stock them :) heheh
C6