I've had guys slip up and say their real name, including my very very first hire. Very very early in my hiring career I wanted to tip a guy but had no cash, so I wrote him a check, which meant learning his real name. But generally I'll call them by their name listed in the ad; if it's something like RideMyCock, I'll ask them "What do I call you?"
Thinking about it, though - it's rare that I speak their names. It's usually just the two of us; I don't need to use his name to get his attention.