Maybe he's stronger indeed, better back off

"Please Josh, don't spoil this party..would you?", you ask, a bit humbled. "You fear me big sister?", he replies, now smiling confidently. "Dear brother, you are a boy and a martial artist; do you enjoy fighting girls? I know that I've few chances against you". Your friends look at you with slight disapproval, especially your female friends, for what looked like an implicit sexiest remark. Josh shakes his head, and snorting walks away. You have avoided the confrontation with your younger brother, but at the price of undermining your reputation.