What are lesbians?

A man is sitting at a bar and see two lovely women across the room. He calls the bartender over and says, "I'd like to buy those two ladies a drink."

The bartender replies, "It won't do you any good."

The man says, "It doesn't matter, I want to buy those women a drink."

The bartender brings the drinks to the women and they acknowledge the drink with a nod of their heads. A little while later, the man approaches the women and says, "I'd like to buy you two another drink."

The women both reply, "It won't do you any good."

The man says, "I don't understand. What do you mean it won't do me any good?"

The first lady says, "We're lesbians."

The man says, "Lesbians? What are lesbians?"

The second woman replies, "Lesbians... We like to lick vagina's."

The man says, "Bartender, three beers for us lesbians."