피융: It's a sound during a bullet flies. ex) 총알이 피융~하고 날아가요. 허둥지둥 (헐둥지둥 is incorrect): When you're very busy and scrruies around here and there, 허둥지둥 could be used. ex) Mika는 바빠서 허둥지둥대고 있어요. 투다다닥: When you're fighting with someone/ people, you could say this expression. ex) Mika는 친구랑 투다다닥거리며 싸우고 있어요. 쓔우웅: When an airplane or other vehicles move really fast, you can use this expression. ex) Mika가 탄 비행기가 쓔우웅~하고 지나가요. I hope this helps MIka^^ If you've further questions please ask me though.