Possible angles: Clarify the terms, offer general info on K-pop fan couples, or explain similar phrases. Also, mention that if specific details are wrong, users should double-check. Need to avoid speculation and provide helpful info based on what's known. Also, since the user might not be a native Korean speaker, the Korean phrase could have been misunderstood.
Assuming that, the user might be asking about a specific ship (s2couple19) being not the main couple in some scenario, and an event in Indonesia on the 18th. However, without more context, it's hard to be certain. s2couple19 eolgongchuga indo18
"Indo18" probably refers to Indonesia and the 18th (day, volume, etc.)? Maybe a fan meeting or event in Indonesia on the 18th? Or a specific group or artist. Possible angles: Clarify the terms, offer general info
But the terms are a bit unclear. "Eolgongchuga" is tricky. Let me think of possible corrections. If it's "eolgongchi a," that might be "he is not the main character." Or maybe "eolgongchi gwaenchanha" which translates to "he is not a romantic interest." Wait, maybe "eolgongchi a" is a phrase used by fans to denote that the couple isn't the main couple, like "not a couple" or "not OTP." Also, since the user might not be a