I'm new at this sexing bunnies thing, but have found it pretty easy and I'm accurate!!!
Bucks = small tube (like a tiny straw) w/ a hole.
Does = triangle type shape, not as high as the buck's "tube" w/ a slit.
To get those results... hold the kit in your lap on it's back. Using your thumb and index finger, put those on either side of their genitals and press until something pops up!
Oh and a buck kit w/ a split penis will be similar to a doe, but it will come up higher like a tube, but w/ a slit down the length of it.
I have each gender of kits, I could try and snap some pics of it later today if that would help. Otherwise, google sexing baby bunnies or rabbit kits and I found a good website for it w/ nice clear photos.