If you meaning is 애교 and using ㅇ, then see this below.
The point is that saying long last pronunciation then usual.
야구 하자. > 야구 하장~
밥 먹자. > 밥 먹장~
들어가도 되나요? > 들어가도 되나용~?
알았습니다. > 알았습니당~
Generally, someone who listening such a word ..ㅇ~ do not like it.
Be carefull only using it to friend.