I totally did my good deed for the day. I was walking with a theater friend, a girl, and stupid boys were catcalling her. 'Hey baby nice ass' and that kind of stuff. She was getting upset, so I turned around instead and said "Thanks! I do squats!" A few bats of my eyelashes and they'd run off.
Don't catcall, it's not attractive. And her gay friend might answer you instead, so if you're not into that, too bad.