Alternatively, could "indonesia18" be a possibility instead of "indo18"? Maybe the user missed a letter. If "Indo18" is Indonesian, maybe it's about someone from Indonesia. But the user wrote "indo18", so maybe it's correct. Let me check the term "Gongchuga" again – yes, in Korean, that's how they say public transportation.
So, the main elements are: a couple from season 2 episode 19 (or couple number 19 in season 2), who met on public transportation, involving someone from India (Indo18), and the topic is trending ("hot"). Maybe it's a viral story of a couple who met on public transport in India or between someone in India and another nationality. s2couple19+gongchuga+indo18+hot
Putting this together, maybe the write-up is about a couple that became popular online ("hot") because they met on public transportation ("gongchuga") and their story is linked to "Indo18" which could be a username or a person from India. The "s2couple19" might be a way to reference them in a specific context like a TV show or social media campaign. But the user wrote "indo18", so maybe it's correct