How big is the snake? Some males can really hold it in if you will. Last show I went to, I purchased a female cinny and was chased down by the breeder because she was a he. The associate popped him and he looked female but the breeder knew he was a stubborn one. If he was sold as a he, he is probably a he. Probing would be another option if you are unsure. You will know for sure once (s)he is proven.