Mixture of the word "Curse" (referring to a swear word) and "Customize". It's When you combine two or more "bad words" together for more of an effect than a just a single swear word.
George: Jill was totally being a total cockshit!
Bill: This "cursetomize" shit is really getting old George.
George: I like trains.
Bill: This "cursetomize" shit is really getting old George.
George: I like trains.
by FroSpeaks April 11, 2011