‘오잉또잉’ is a kind of a slang(when we are curious about something..?) But most people don't use this word because it sounds too cute.. sounds like child word haha (source: https://hinative.com/ko/questions/4570057) Recently, jimin of BTS left '또오잉’ with a photo in his Twitter.

It seems like it it newly made word on the internet. Even I don't know what it means with this one word. But I am sure I can tell you what it means if I get the whole conversation or context.