Check out this short article from VPI , has some good pictures what you should be looking for.
http://www.vpi.com/publications/dete..._sex_of_snakes
Keep in mind that popping or probing most likely isn't any more pleasant for the snake than it would be if someone was doing that sort of thing to you so don't abuse the snake by trying over and over. If you think you need to check again give it a day or two so that it can relax about a crazy predator playing with its privates.![]()