Go to "addons/chatdoodler/lua/autorun/server/chatdoodle_base.lua".
( I hope to make this easier in the future. )

Edit the items after the equals sign, or even progress further if you dare.
Comments on the side display their usage...

Lines 1-14
----- ONLY EDIT THIS \/
local doodleword = "doodle" -- ALL LOWERCASE; WHAT THEY SAY TO BEGIN DOODLE
local playerblacklist = {} -- A LIST OF BLACKLISTED PLAYERS BY STEAMID {ID1, ID2}
local playerblacklistnick = {} -- A LIST OF BLACKLISTED PLAYERS BY NAME {CODPLAYER, NUBSKRUB}
local minpixelcount = 1 -- THE MINIMUM AMOUNT OF PIXELS TO BE ACCEPTED
------ ONLY EDIT THIS /\
------ LUA CODERS CAN EDIT BELOW \/

------------------------------------------------------------------------
function authPlayerDoodle(ply)
	return true -- Ply is the player trying to doodle, add conditionals and checks here at your pleasure
end
------------------------------------------------------------------------
-- EDIT NO FURTHER --