sexing: palpating

[Will0W783]

I'm not sure what you mean by "palpate." The only fairly accurate means of sexing snakes is with a sexing probe that I know of. Very young snakes (neonates up to several months after birth) can be "popped." This is done by rolling the thumb and forefingers to create pressure on the cloacal areas that causes the hemipenes to pop out in a male. It's not as accurate as probing though, because once the snake has developed muscular control it can still hold in the hemipenes, resulting in males being mistaken as female.
Even probing is not 100%...there is some variability in both sexes and between species. You select an appropriately sized probe, lube it with some KY or Vaseline, and gently insert it into one side of the cloaca, down towards the tail. In males, the probe will go inside the inverted hemipenis; in females it is stopped by the scent glands. You mark how far down the probe has gone and then measure the number of subcaudal scales it passed. Males of most species are 8+, while females are >/= 5.