The Carrot and the Stick

'Why do so many men like to spank a girl's bottom?' Beth asked.
The female psychiatrist had not expected the question but was ready with an answer.
'The female bottom is the most beautiful part of the human anatomy,' the psychiatrist said. 'It is the portal to paradise, to the hidden chambers of pleasure.'
'But why spank it?' Beth persisted.
'Power and dominance,' the psychiatrist said. 'The priapic male is the hunter, the submissive female the victim, the more submissive the better.'
'Oh,' Beth said, disappointment in her voice. 'Is that all it is?'
'No,' the psychiatrist said. 'That is not all. There is another hidden truth behind the obvious.'
Beth was puzzled. 'What can that be?'
'Come over here,' the psychiatrist said. 'And I will tell you. Lie over my lap and I will show you.'