I was thinking they'd behave sort of like chalk, but after starting to add the flesh tone over the blue/green, I was disappointed to find it was more clumpy/waxy (like crayons).
I freaked out a little when I started adding red...so I tried blending it some with q-tips (fixed it some).
I still don't have a hang on the blending. It seemed like it just ended up scraping off the layer underneath. I'm not sure if it's because the pastels were so old, or if they usually behave like that. I'm still not sure if I like this medium, it didn't quite turn out as I imagined (and I lost a lot of the depth of the sublayer colors).