"The lecture on the Supernatural." joke

A professor at the University of Greece in Kalamata is giving a lecture on the supernatural. To get a feel for his audience, he asks: "
How many people here believe in ghosts?"
About 90 students raise their Tsigara(cigarettes). "
Well that's a good start.
Out of those of you who believe in ghosts, do any of you think you've ever seen a ghost?"
About 40 students raise their Tsigara(cigarettes). "
That's really good. I'm really glad you take this seriously. Has anyone here ever talked to a ghost?"
15 students raise their Tsigara(cigarettes). "
That's a great response. Has anyone here ever touched a ghost?"
3 students raise their Tsigara(cigarettes). "
That's fantastic. But let me ask you one question further. Have any of you ever made love to a ghost?"
One student way in the back raises his hand. The professor is astonished. He takes off his glasses, takes a step back, and says, "
Vre pethaki mou,(my dear child) all the years I've been giving this lecture, no one has ever claimed to have slept with a ghost. You've got to come up here and tell us about your experience."
The man replies with a nod and a grin, and begins to make his way up to the podium. As he ambles slowly toward the podium the professor says, "
Well, tell us what it's like to have sex with a ghost."
The student replies, "
Ghost? Pou re Gamoto!(Oh man F*#@K) I thought you said 'goats!"