So what do you do if some stranger hits on your girlfriend or calls her a whore if your not there?

So guys what do you do when some strangers hit on the girl of your dreams behind your back while your at your place? My girlfriend told me that guys call her a whore or beep horns at her while she walks outside. I got my baseball bat on me. But seriously what do you do when that sh1t happens? What would you do if you WERE there?