You can use the phrase anytime you are trying to say "deez nuts" especially if it's large. Or if you just feel like saying it.
Named after the gif "Burkina Fasoball says 'Deez Nuts'" but shortened down. Etymology comes from Burkina Faso being a large producer of (deez) nuts.
Friend 1: breh you so fresh
Friend 2: not as fresh as Burkina Faso deez nuts in your sister's mouth!
Friend 1: Ayo, what my sister did to you