You can buy probe kits and try to probe your snake yourself(with help from a friend also), but it's risky and there's a chance you can injure your snakey. So it's best you don't try it on your own. As for any other ways other than probing...I don't think theres many characteristics that seperate a female ball from a male ball, other than usually the females grow bigger. Some people also try to go by the anal spurs. It's said that males will generally have longer and curvier spurs and thicker tails than the females. But it's not 100%.