Some snakes are easier to pop than others. I am better at probing than popping but if I pop a boy, I'm comfortable with that, although I always probe to be sure. If I pop a girl, I'm not so confident, so again I probe to double check. The ones I have popped a boy have always been boys. Some of the ones I've popped girl have turned out to be boys. Get help from someone local, then get good at one or the other.