There's a man on Wall Street walking around calling himself the "sex ninja." A New York stockbroker in his late 20s, Mark says he knows how to cheat. "I am a ninja of infidelity." He told New York Daily News. "I have cheated on many of my girlfriends, but never once been caught or even suspected of cheating. I really am that good." Cue the united eye roll. So what's Mark's secret to never getting caught? He's got a few rules that he follows... Here's what you had to say: Erin commented via Facebook: "Why would he put so much effort into living a lie? If you don't want a relationship, then sleep around and date a lot of people." Inyourfaceflanders wrote: "It's just a matter of time before Mark gets caught."