RuLyn,
We pop our freshly hatched babies. When they are still young, their muscles aren't very stron yet, and it is very easy to get a male to evert his penes. It takes very little pressure at all. I will however double check their sexes every month or so, just to make sure I didn't make a mistake. Also, we will double check the sex prior to shipping to a customer, if the snake was for sale, to make sure we are sending out the correct sex.