How do you know a female corn snake from a male?

The most reliable way of sexing a Corn Snake is by 'probing', a metal probe is inserted into the opening of the pouch behind the vent, in females the probe will extend the length of only 1 or 2 subcaudal scales, while in males it will extend 6-8. PLEASE NOTE: THIS PROCEDURE SHOULD ONLY BE CARRIED OUT BY SOMEONE QUALIFIED TO DO SO AND CAN SERIOUSLY HARM AND CAUSE GREAT PAIN TO YOUR SNAKE IF DONE INCORRECTLY!