Mantap-Mantap Taras come from a DOTA player who build Heart of Tarrasque (item in game) and Winning the game or overcoming the game by buying their Heart of Tarrasque.
Sentence "Yeah i'm Winning" Become "MANTAP-MANTAP TARAS"
Mantap jiwa = jiwa yang mantap or very strong soul
Mantap jiwa means very good in Bahasa Indonesia, but it has different feeling when u using it. You should put the emoticon 👍 to express this feeling. Mantap jiwa also can be as Mantap soul. Jiwa means soul.
Eneng: How's my cooking?
Dedek: Woah.. Mantap jiwa! 👍 I very like it!!