Rhino Horn Pills

First girl: 'I hear you're going out with a rugby player. Is he any good in bed?'
Second girl: 'No, not much. I got him to take some rhino-horn pills.'
First girl: 'What for?'
Second girt: 'They're supposed to be an aphrodisiac.'
First girl: 'Did they do any good?'
Second girl: 'Yes - but the trouble is that now every time he sees a Land Rover, he charges at it.'