So - does the Namespace operator (and IPV6 address separator) have a specific phonetic pronunciation? Something onomatopeic? “Colon colon” suffers from having too many syllables.
If there's no generally accepted practice, I submit that whenever “::” needs to be vocalized, it should be pronounced “blup blup”, (and correspondingly, that the colon be pronounced “blup”). Enunciation is frowned upon, so the two sounds should run together.
(Yes, I'm one of those people who uses “Bang” for an exclamation mark (depending on context), “Wack” for a backslash (and sometimes the forwardslash), and pronounces M$ “Em ta-ching.”)