So I tried.. I really did.
Joel was not as cooperative as I would have liked, and I actually have hurt my finger recently in a knife wielding accident, so this wasn't the best time for me to do this, but I did it anyway!
Lets see if I can explain this as much as I can with the photos. Above is how you would hold the tail. Put your pointer finger across the base of the tail, and the thumb and forefinger of your other hand holding the tail.
Bend gently back to expose the vent.
Roll your pointer finger towards the vent, while also pushing gently down and out with your thumb.
Hemipenes like these will show up if it is a male. I wish the flash were on (which Joel completely ignored me about) so that you would be able to see the color and detail more clearly of the vent area... But my "finger was in the way".
Here we have a female. Notice that there are no penes at all, albeit there are a few nubs. Nubs are typical, but if they are not more than 3-4mm long and red, they are not hemipenes.
If you notice the base of the vent, it is getting a bit red in the scales. This is typical of bruising behavior in light animals (this was a Pied). So if you see a lot of red around the vent, STOP. You are pushing too hard.
So I hope to be able to get a more willing photographer and try this again soon. Until then, this is all I can do.
I hope this helps, and let me know if you have any other questions.
Have a fantastic weekend, my friends!