Who Keeps Saying Those Things?

A man walked into a bar after a long day at work. As he began to drink his beer, he heard a voice say seductively "You've got great hair!" The man looked around but couldn't see where the voice was coming from, so he went back to his beer.
A minute later, he heard the same soft voice say, "You're a handsome man!" The man looked around, but still couldn't see where the voice was coming from.
When he went back to his beer, the voice said again, "What a stud you are!" The man was so baffled by this that he asked the bartender what was going on. The bartender said, "Oh, it's the nuts -- they're complimentary."