Make a SWEP Active?

[Mr. Wepz.]

Hey guys, Currently im working on a SWEP (if i can call it like that) but it haves to be like the disguiser, you buy it, you press a key and it does something. At the moment im busy makeing "Running Shoes" when you hold Shift you can sprint for 5 seconds then your "stamina" refils, but how do I make that the SWEP is Active like the disguiser? Couldnt find the LUA source of the Disguiser in the gamemode files

Thanks :D