One of the more common ways that we try to differentiate a male and a female or try to decide which one is which is at the base of the tale, especially in your boids, they will have a vent spur here and here along the sides. These spurs actually used to be legs millions of years ago.
In the males these spurs can be a little bit longer and they're used to stimulate the female and hold the female in place. A male's tale may be a little bit stronger, a little bit bigger for the same reason. Snakes have hemite penises, hemipenises, one along the side here and one along the side here to the vent.
One easy way that we normally will find out if it's male or female is we have small probes that we actually can slide in. In a male that probe will normally go about five scales, whereas in a female, they can sometimes have a little papule in here but it only goes a little ways. It won't go down five. So you'll move it in and back and if it's deep, five scales, same thing on this side, then you're pretty sure that you've got a male.
Another way that you can do it is just popping. You just put your thumb and roll your thumb this way and the hemipenis will protrude from here and here.
Some difficult snakes we actually have to inject saline. We do this in lizards as well. You do it behind, under the skin, and as you inject it into the sheath or the lumen, it actually forces the hemipenis out.
And that's the way that we figure out whether we've got a male or a female.