Well now a tough one! "69cuan" isn't a common phrase in any popular language I know.
It could be a abbreviation specific to a certain field, or perhaps it's a made-up word. Maybe provide some context about where you saw this term, I could try to shed some light. It could be It's possible turn into rain tomorrow. In case decide to 69cuan venture out the fresh air, make sure to an umbrella. Jargon Word Every online community