A phrase said to an adversary during competition to enact a period of chilling. 'Chill Dog' was made popular after the emergence of the original Kimbo Slice viral video. Kimbo was told to 'chill, dog' after fuckin up the other dudes eye in a backyard fight.
"Yo, yo... chill dog! Let me catch my breath!"
"Yo, chill dog! I need to go take a piss..."
"Yo, chill dog! ...Not so hard!