(pernounced "scoop" but has an awkward tone to it)
Skoop Skoop referances the sound a cops siren makes when they activate the siren for a short burst, so emphasis should be given to the second 'skoop.' (skoop skOOP)
It can be used to replace a variety of words to include, Police, Cops, Hey, things pertaining to smoking, avoiding work, and can also be used as to replace "Yes" when asked a question.
Justin: Hey man!
Me: Skoop skoop!
Me: What do you want to do tonight?
Justin: Skoop skoop!