I'm trying to duel people 500tc and they don't want to duel a master belt, so I decided to make an alt so people weren't scared of my belt but they always know who I'm swaves by my belt (there aren't many australian players), I'd like to know to to use the toribash flag instead so people don't find out who I am!

(I'm not going to use a proxy, just tell me another way)

There really isn't another way. Use vpn or have a newly created account that hasn't got a flag yet. Unless TB magically implemented a feature to hide your flag (which they haven't), you have to learn to use proxy or vpn.