What does It mean when someone says you are dangerous?

I am a guy and have been told this by a couple of girls I've dated. They were not refering to how I treated them or me being a "bad" person. What they were refering to was the size of my penis in that it is much bigger than most guys. They both meant it as a "backhanded" compliment but it's also made me realize how lucky I am to possess one.